[TYPO3-mvc] 6.2 BE List Module raises PHP Warning: Input variables exceeded 1000.

[g4-lisz at tonarchiv.ch]

Hi list

A few hours ago, everything was working fine...
Now I get an error when I try to add a record to my extbase extension,
using the "List" BE module:

"Validating the security token of this form has failed. Please reload
the form and submit it again."

In the Apache error log, there's a line:

PHP Warning:  Unknown: Input variables exceeded 1000. To increase the
limit change max_input
_vars in php.ini. in Unknown on line 0, referer:
http://xxx.com/typo3/alt_doc.php?returnUrl=mod.php%3FM%3Dweb_list

Why is this, and is it safe to increase this limit?
Is this a hint that something is fishy with my model / class?

Cheers,
Till