Hi @MaximeGendre ,

Probably you hit some streaming limitations that apply to Unit Catalog standard access mode. Assuming of course you're using standard access mode 🙂
But one of the limitation they introduce at Databricks Runtime 14.0 and UC cluster is following:

Compute access mode limitations for Unity Catalog | Databricks Documentation

Which is exactly what you're experiencing. So for Unity Catalog enabled clusters and DBR >= 14.0 print within foreachbatch will write output to driver's log.