Reply To: admin columns not working

Hi,

Hereby the code:

https://ghostbin.com/paste/ssuu2

As said, this code works fine for one CPT, but doesn't for another. Only difference between both are the funcion-titles and post-type names.
Could it be caused because of a earlier error where something is going wrong in building or filling a database table?
What makes me think that is when I rename 'suppliers' to 'sponsors', I get the same issue.