Custom fields not showing in form
Hello there,
I'm trying to create custom fields (just simple strings, not synched with SFDC), to collect different purposes on Marketo, as I always done. Now I have a set of 6 custom fields called "Free field 1", "Free field 2", etc.
Two examples:


Funny problem: in a form editor, completely blank and new, I can add ALL my custom fields. BUT, and here is the problem, in an already existing form, I can't see some of the additional custom fields that I've created right now.
Why? Where are they?

Just for a better explanation: no fields count limitation, I can add more and more fields as I need. And no, I didn't already add them, they didn't exist before now. And yes, there are other custom fields.
It seems that I can't add more custom fields named "Free field". Is it possible?