I found the answer in the docs here :

https://docs.espressif.com/projects/esp ... alloc.html

leaving the post here as it may help others.

We know that we can pin tasks to a specific core. What about ISR's? How is the core that they will run on defined? I don't find anything about this in the docs.

I saw previous posts about this odd error but no explanation about what the issue is.

We have two ESP32s3 applications both of which use a hardware timer. They both use the timer in a similar way, but with one small difference.

In both cases we configure and then enable the timer, in exactly the ...

I see this same issue exactly, with IDF 5.3

I just ignore the errors, the junk on the terminal is annoying but the hardware works fine.

It really seems like a bug, the timer IS for sure getting enabled before I try to start it.

Any fix for the spurious error?

(EDIT - the issue seems to be fixed ...