Thanks for the explanation. I'd read that thread but thought the change was supposed to only modify the behavior when explicitly specifying the --debugger option. That also seems to be the gist of the original RedHat bugzilla request that prompted the thread:
This might not be obvious.. I had assumed that --debugger does two things: load the debugger profile *and* turn on extended debugging features, from the description:
Arrange for the debugger profile to be executed before the shell starts.
Turns on extended debugging mode (see the description of the extdebug
option to the shopt builtin below).
Maybe the description of the extdebug option to the shopt builtin can be modified with something like
If set as part of shell invocation, the debugger profile is executed before
shell startup. If the profile cannot be executed, the option is not be enabled.