We're having issues with our Delphi-client where it receives empty datasets.

Response fr om WRC : 

The problem was that Delphi switches from read uncommited to read commited mode and we had a problem there with the joins on null values. The fix will be included in the next maintenance kits for 2017.2.x.  The change already went into 2018.1 so it will be in all versions 2018+.