flutter-desktop-embedding: embedder crashes on linux with latest flutter

I did an update of flutter and rebuilt libflutter_engine.so with --runtime-mode=debug but running the app with the embedder is causing a segmentation fault. 5223 Segmentation fault (core dumped) ./app/app.bin Is there any way to view a call stack or something to help with why this might be happening?

As usual all help appreciated.

Many thanks.