I have found an apparent bug of the abusefilter, related to Special:CreateLocalAccount.
We have filters including the following lines:

equals_to_any(action, "createaccount", "autocreateaccount")
&    rmwhitespace(accountname) rlike "SOME REGEX"

This prevents forcible local account creation as expected if the account name matches the criteria, but the problem is that no abuse log is shown when forcible creation is barred. When you evaluate action === "createaccount", you can use a bunch of built-in variables like user_name and user_groups in addition to accountname, but as for "forcecreatelocal" (as in list=logevents), something like !"sysop" in user_groups doesn't work and there's no way to prevent the relevant filter from being triggered on forcible account creation (note also that there's no way to see which variables are available for "forcecreatelocal" since abuse log doesn't show up). I tried disabling the filter to see if that resolves the issue, but even after turning it off (and leaving it some minutes), it keeps getting triggered and we can't use [[Special:CreateLocalAccount]] in the way that it should work.

We would appreciate it if someone could look into this matter.