Hi Jim,
I suggest to create a representative BEx query which reproduces the strange behavior and run it in the backend using t/code RSRT. Please note any error messages which might occur.
I also suggest to activate the MultiProvider once again. Please note any error messages which might occur.
Last but not least, please implement the SAP Note which I found, it is applicable for SAP BW 7.30 SP10 (the error is solved in SP11).
Best regards,
Sander