I hav't been able to get a core dump (and backtrace) yet, but when I remove a feed after liferea's been running a litle while, it terminates wih a segfault.
Starting up a fresh instance usually lets me delete the feed with no problems, but I've noticed that if there's an update job going on after startup, deleting a feed often gives another segfault.
That said, most of the time there are no active updates running when the crash happens. I'll try to get a stack trace. (svn r5401)