for the past month, my users have been getting completely random internal server errors when posting/replying.
and I mean random.. someone will have it happen with every post in a certain topic, but it won't happen to any else, then suddenly, they don't get the error.
one day I can post to a topic, it works, I'll post a again later, it doesn't work

there is no rhyme or reason, no pattern.

all I see in the error logs is AH01215: [vanning.com/www/threads] Program mode requires special privileges, e.g., root or TrustedUser

the admin is saying it's the software (UBB), however I had made no changes in a very long time when this had started to happen.

using version 7.6.1.1
PHP Version 5.5.9-2ubuntu4.22a

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