Might be a new bug, might not be. This is showing up in M54, but unfortunately all crash reports are lumped together with other sync IPC hangs.

Sample report for this IPC: go/crash/9577ffde00000000

This implies that ResourceHostMsg_SyncLoad is not getting a response.

This could be due to a bug in browser-side resource dispatch, or it could just be a symptom of other browser hangs. Needs further investigation; assigning to myself until I can triage further.