GN 4 harvester not able to harvest a pyCSW endpoint

Hallo community,

We have encountered a scenario where the harvester in our GeoNetwork 4.2.2 is not able to harvest records form a pyCSW endpoint. However, the harvester in a GeoNetwork 3 instance is able to successfully harvest this endpoint.

In troubleshooting we are trying to understand, was there a significant change in the harvesters between GN3 and GN4 that this is happening? Has anyone else encountered this and were you able to solve it?

Thanks!!