Triggers on rdb$procedures and rdb$triggers do not seem to cause access violations when creating or altering objects of those types, but a trigger on rdb$relations does. Once the trigger was in place and committed, I got an AV from simply doing:

create view x as select * from rdb$database;

I'm attaching both the scripts to setup the test case (which works for procedures and triggers, but not views), and the drwatson PDB output from the crash. (It's the log file, not the binary dump, let me know if you need the other.)