Hi, we have the same issue since few days when executing notebooks from Azure Data Factory :

AnalysisException: Undefined function: count. This function is neither a built-in/temporary function, nor a persistent function that is qualified as spark_catalog.default.count.

We tried a lot of things to find where is the problem but didn't find yet, support ticket has been opened ...

For now we think that it is something relative to the SparkContext, a link to jar seems to be broken, if we detach and re-attach the notebook (no need to restart it) it works.

11.3 LTS