compiz: segfault at 0 ip af976f3d sp bfbd6ff0 error 4 in libunityshell.so (Disco)

Unityshell crashes when starting and screen goes back to unity greeter. This seems to happening after ccsm python3 port. Though downgrading compiz works, I suspect it is breaking when compiling against newer libraries.

Syslog doesn't really say much other than this:

compiz[7669]: Invalid MIT-MAGIC-COOKIE-1 key/usr/bin/compiz (core) - Fatal: Couldn't open display :0

unity-panel-service[7677]: Invalid MIT-MAGIC-COOKIE-1 keyUnable to init server: Could not connect: Connection refused

Log: https://paste.ubuntu.com/p/tZXCmYBQgy/

I try to get stacktrace running unity --advance-debug from tty in flashback metacity session, but I am getting "error debugging symbols" and it freezes after that.

Partial Trace: https://paste.ubuntu.com/p/hvmhbRVDP8/

Update:

1) It seems segfault occurs only on 32 bit on older version of intel (i915, 965).

2) On Ryzen DISPLAY is :1, manually setting it :0 works.

3) On 64 bit (all machines) user can't login first-time for every new user because of timeout error of unity7 service. 2nd time it logs in just fine. Time out error is most likely some regression with gsettings backend of compiz.

https://community.ubuntu.com/t/testing-unity-session-in-19-04/8451/166

OS: Ubuntu 19.04
Graphics: Intel n4200/GME 965/, Amd A10

Edit: Alberts Muktupāvels who authored ccsm python3 port confirmed it, so setting it as confirmed.