Thanks for following up on this. I will take a look at it at some point and will give you feedback. Just writing to let you know that I saw it.

I have finally got around to take a look at this. Great to see how this can be reproduced by using vanilla DRF classes.

It is though as I expected that this fix does avoid the exception, however the output of the fix is notJSON:API compliant. It simply returns

{"errors":None}

but the value of errors needs to be a list and each error object must at least have one member. I think the easiest is to add a single error object with the status code as a string.