How to fix that new users show up again in subsite of a Multisite?

That its expected behaviour, you have to manually add the user to the site and select his role, you go to All Sites, Edit a site, then select the Users, tab:

enter image description here

Related Posts:

  1. wordpress multisite, how to keep user on subdomain throughout registration process?
  2. Prevent user creating new users with specific roles
  3. How to add multiple existing users to a multisite site?
  4. WPMU – new users are automatically subscribed to the main blog – how to prevent that?
  5. Displaying a message upon user registration
  6. Add a user to a specific blog when they register?
  7. Four columns in the wp_users table
  8. Easily adding multiple existing users to a multisite site
  9. Possible to have duplicate usernames on different two multisites
  10. Modify new user email notification in network admin screen wp multisite
  11. Users getting linked unwanted to main mu in WordPress multisite (WPMU)
  12. Can’t activate a user on multisite install
  13. A different role for each site in a multisite
  14. Multisite “Skip Confirmation Email” Log Out Problem
  15. Using a number for limiting registering or banning on multisite
  16. How can I un-reserve a pending username registration?
  17. Is there a is_user_logged_in() for multisite?
  18. WordPress Multisite allow site admin to add user without email confirmation
  19. Network not displaying all sites and users
  20. WordPress Multisite – When a user signs-up on main site, how to add the user to a subsite
  21. How to use alias domain for multisite installation?
  22. Give to site admin the option to “skip confirmation email” when adding new user
  23. How does WordPress connect sites and the wp_users table?
  24. Get first_name and last_name on user_register hook
  25. Can’t add user to blog on registration (Multisite)
  26. Allowing logged in users to comment without moderation across a multisite installation
  27. Can you have multi-site WP and keep users separate?
  28. WordPress 3.2(Multisite) – How to add custom user meta fields to signup form?
  29. the blog owner multisite
  30. How can I get multisite primary blog (url or path) for current user?
  31. Why can’t I delete original user in multisite? Options for manual removal
  32. Can I use multisite functions in a single-site installation?
  33. How to add edit users capability to a custom role?
  34. User registration on sub site
  35. In MultiSite, can some users automatically have Site Admin rights on all sites, without granting them Network Admin access?
  36. Disable domain redirect
  37. How can I delete a user from entire multisite nework
  38. delete_user_meta : how to delete all the metadata of a given user (witout SQL)
  39. How to search users globally on a multisite install?
  40. Update User Role Across Network when Main Site User is Updated
  41. Get the User ID Who Owns a Given Blog ID in Multisite
  42. Make a user administrator to a sub directory site and a contributor to main site in multisite network
  43. Query users by capability – uninstall/deactivate callback
  44. What sites are you registered to when joining a multisite?
  45. How to change user starting role in WordPress MultiSite?
  46. How do you disable account activation in WPMU and then log the user in right away?
  47. Auto creation of multisite blog on user registration
  48. Multisite – user email activation links broken
  49. Add menu items/actions for multisite users who are registered on the network but do not have a role or capability in any sites
  50. Is the Multi site functionality a viable option for Country and Language targeting?
  51. Good way to block users within a multisite setup without deleting them?
  52. Subsite access without being a member of the subsite in wp multisite network
  53. Using the standard WordPress “New User” interface on a multisite
  54. Create Custom Multisite User Role to Reduce Capabilities
  55. How can you override the is_multisite check in wp-login.php for individual login/registration?
  56. Obtaining user table for one site on multisite set up
  57. WordPress stuck in deleting user
  58. Get users registered 30 days ago(or more)
  59. Bulk Move Users from one site to another within a network ( Multisite )
  60. WordPress Multisite – Load users using custom query
  61. User registration on two sites in same multisite
  62. How to change a user role after registering in multisite?
  63. Delete user from multisite when removed from subsite
  64. Combining user database tables while keeping all other data in seperate for multiple sites?
  65. WordPress Multisite Add User
  66. Sharing users across multiple sites, each on their own database
  67. Customize or avoid new admin email address notification
  68. Using Same User Database on Subdomain
  69. How to get the blogs owned by a user?
  70. User registration is currently not allowed
  71. How to redirect user after session timeout
  72. Multisite ‘Welcome User Email’ SITE_NAME returns ‘network’ name, not the name of the blog
  73. User registration on wordpress multisite
  74. How to use the same users table on multiple wordpress sites
  75. Automatic registration on main site upon user registration on Multisite
  76. Register a user only to the root blog – WP Multisite
  77. Activate User account for Sub Site broken
  78. How to allow mixed case characters in multisite site name?
  79. Multisite – each site with it’s own set of users
  80. Multisite – site user limited only for this site
  81. WordPress Multisite Network Subdomain
  82. Importing Posts into New Website with Same User ID’s
  83. WordPress automatic Login on other page?
  84. Multisite: How to bypass wpmu_signup_user_notification and add my own notification logic?
  85. Allow users to register on multisite through WooCommerce using the same email address
  86. Activation of new Registered site fails on multisite
  87. Is Multisite the RIGHT option for my case?
  88. Should I use MultiSite for a subdomain based wp site?
  89. User registration problem on multisites web
  90. Multisite – User creation for second site from first site?
  91. How to create child/sub user under parent user
  92. How to Create WPMu New User?
  93. How create a multisite setup with “phantom” accounts and passwords?
  94. Is there any way to give all users access to one blog in a multisite network without using a plugin?
  95. Redirect authors from upload.php url to Home page in Multisite
  96. WordPress multi user registration sites
  97. How to use same email for multiple users? [duplicate]
  98. WordPress Multisite restict user access
  99. Multisite Login Access Restrictions
  100. Change a subsite Admin role of a WordPress Multisite after 24 hours registering