Hello,
Tested on two different Apache servers, with forums with around 20000 posts, when running a bbcode reparse, the STK is failing with the following error :
Reparse bbcode - Fatal error: Allowed memory size of n bytes exhausted
Obviously, when I increase php.ini 's setting about memory_limit to a stupidly huge value, it can run, but I also read some other hints like (https://www.phpbb.com/customise/db/official_tool/stk/support/topic/135796?p=424921#p424921) that seems to advice some other way.
On smallest forums (with lot less posts), there is no issue.