"At least one referenced Activity Class Schema is invalid: ,282 from PROCESS.prepareExecutionProcessModelIds on execution04"

Hi there,

We're having issues with four process models in one of our lower environments. Three are started from a process start form, and one is just a subprocess in another process model. The error must be occurring before the process actually starts because the process models do not show in Monitoring when the error occurs.

It will fail with this error on screen:

And this error in the logs:

2024-10-29 14:59:28,816 [ajp-nio-0.0.0.0-8009-exec-54] ERROR com.appiancorp.rest.shared.FallbackExceptionMapper - Internal Server Error on REST API invocation.

SignalException: Received signal At least one referenced Activity Class Schema is invalid: ,282 from PROCESS.prepareExecutionProcessModelIds on execution04

It doesn't happen every time - it's only failing when the process hits exec engine 3, 4, or 5. Engines 0, 1, and 2 all seem to be fine.. It is also only happening in one of our lower environments and not the other three. We recently upgraded to 24.2 and it did not resolve the issue, nor did migrating from Windows to HA Linux. We've exhausted all efforts and even Support is stumped on this one.

Any thoughts?