LLDB error / message thread deadlock on Monterey

I am compiling a project for the first time on a MBP M1 Pro running macOS 12.0.1, using CLion.

I seem to be hitting a deadlock without many clues as to why. When I hit pause in the debugger I see the following:

Does anyone have an idea of how to further debug the issue?
(short of putting loads of breakpoints/DBG statements to try and narrow it down)

This happened only when attaching the debugger in CLion. And it happened when a login form appeared. Now that I logged in without the debugger attached, I can run it with the debugger (the login is saved).

Ah I think this might be the clue: LLDB is complaining with

error: need to add support for DW_TAG_base_type 'auto' encoded with DW_ATE = 0x0, bit_size = 0

I’m using the bundled LLDB with CLion, which is version 12. I tried GDB but that crashes completely.