I’ve solved the issue for us. We are using ACF JSON to save the groups inside the theme, however, in one of these groups there was a repeater field without ‘child’ fields, which caused this issue. Removing this field completely fixed it!
@hube2 It seems to only be a problem when already having lot’s of large field groups that are being loaded with acf-json (local). Even displaying some groups (in this case on an options page) gives issues.
@hube2 Our memory limit is 512 MB, it really is exactly the same issue as @nickxd is/was having. Something inside ACF is causing an infinite loop, and with that it surpasses the memory limit. Even cranking up the limit to 1024 MB or more is not the solution.
@hube2 That is correct, however, if I turn XDebug off, I get an out of memory error, because of the too many nested function calls, so that won’t fix the real issue we’re having.
@nickxd It looks like we are having exactly the same issue. Did you find a solution for this?