plugin wants to update to wrong plugin

The updater works based on the plugin’s installation path and the name of the file containing the header. I’m guessing both plugins are housed in a /breadcrumbs folder (since that seems to be Yoast’s setup.

Though Yoast’s plugin uses yoast-breadcrumbs.php for its main file. I’m assuming you’re using a different filename, so you have indeed run into an interesting problem.

I’d take a closer look at your system, because the updater sends two variables when checking for updates:

• “plugin_slug” … in this case likely breadcrumbs
• “plugin_path” … /breadcrumbs/yoast-breadcrumbs.php

There’s a naming collision between your system and Yoast’s if they’re both called “Breadcrumbs” to WordPress. I’d recommend changing your system to put things in the /kaiser-breadcrumbs directory instead. That might solve your problem.