I have exactly the same problem as others have reported. This is very annoying.
Have been running a PS3 with GPUGRID for approx. one month, and one more PS3 for 4-5 days.
First time I experienced a WU with credit 130-135 was aug 9. Then during the last week, I have 3 of them.
I also have some days where no GPUGRID credit was granted at all. It may have to do with the fact that I had some downtime during installation of the second PS3,
but I'm not convinced.
I am running YDL 6.1. I also run the Primegrid AP26 search, but only with a ressource % of 1.54. Receiving only minor credits as expected.
I also feel that this issue may have to do with the interruption of a WU. When BOINC manager is closed down, it seems that the process continues to run.
Then when YDL is being shut down, it always claims that some processes refuses to close. Meaning that the processes are killed by YDL during final close down.
When YDL is re-booted and BOINC manager re-started everything looks OK (the elapsed time of the WU looks pretty much the same as before), but maybe it's not.
Have not found any messages in the log which helps explaining.
I am looking forward to some day where I receive full credit on both machines. That would be some change...
PS: I also have a WU with status 'redundant result' and runtime 0.