Builder hangs at the end of a build (non-AMD64 platforms)

[jchown]

My Github actions have stopped working (apologies, I can't say for sure exactly when - it occurred after I hadn't touched the project for a while). It is a .NET Core 6 build.

Everything looks like it succeeds but the process never exists:

#15 exporting to image
#15 exporting layers
#15 exporting layers 0.9s done
#15 writing image sha256:e059b6102f2b0362fe5920e480561c33d0df7ee82ff0f65f5e4fbfc6bd5cc0d3 done
#15 naming to docker.io/***/aarch64-ozric-addon:0.8.0 done
#15 DONE 0.9s
[10:32:07] INFO: Finish build for ***/aarch64-ozric-addon:0.8.0
[10:32:07] INFO: Create image tag: latest
[10:32:07] INFO: Start upload of ***/aarch64-ozric-addon:0.8.0 (attempt #1/3)
[10:32:16] INFO: Upload succeeded on attempt #1
[10:32:16] INFO: Start upload of ***/aarch64-ozric-addon:latest (attempt #1/3)
[10:32:16] INFO: Upload succeeded on attempt #1

It sits and hangs after this output until the build agent times-out and kills it.

I have narrowed it down a little - AMD64 architecture works fine, but ARM v7 and AARCH64 both lock up like this.

Do you have any idea what I might be doing wrong? My project is here if you need to poke around.

[jchown]

Correction, it is now just ARM v7 that never completes.