In search I found https://bugs.xdebug.org/view.php?id=2222 which seems to be tangentially related, however in my case there is no __desctruct method in the object, as well as that xdebug crashes in the middle of the application, which is worse than that issue.

WARNING: [pool www] child 1457777 exited on signal 11 (SIGSEGV - core dumped)

xdebug 3.3.2
PHP 8.3.8 (php-fpm sapi)

xdebug.mode=debug,develop

• removing "develop" fixes the problem
• this issue happens even if no debug session is active and no develop functions have been called either
• memory limit is 4096M, php memory_get_usage() reports memory consumption of between 40-180M (depending on how the issue is reproduced) in the line directly before it segfaults
• the code that segfaults is a throw that is caught with a try/catch
• the issue doesn't happen on the first occurrence/invokation of this throw, but after x calls to the throw it suddenly segfaults (might be another cause, just an observation)
• it seems that this is related to throw inside a closure and/or method invoked on a dynamic object (e.g. new $foo()), but again, this is just an observation
• there is no loop/recursion