[Users] segmentation fault when disabling a ruleset while it is being processed

[Marco]

Hello,
I run Claws Mail 4.0.0 on Ubuntu 22.04.

I've enabled a ruleset to delete certain messages.
If I open an NNTP folder, it will be processed.
While it is being processed (it takes very long), I disabled that rule
again. It resulted in a segmentation fault, no further messages in the
terminal.

How can I debug this?

-- 
kind regards
Marco