Based on our discussion in the comments I think the issue you’re experiencing is that you’ve got a slug conflict with WooCommerce ‘downloads’. Your CPT isn’t conflicting but the slug it’s applying is probably conflicting with WooCommerce’s slug for downloads.
To rectify this, simply prefix your slug or adjust it:
/dls/
/nthn_downloads/
/themename_downloads/
Anything of that sort that’ll differentiate it from the download endpoint & urls that WooCommerce generates for downloadable products should be sufficient.
Using the CPT UI plugin you would just edit your Post-Type and scroll down to the area pictured here…
