Stats Problem

Hi ppl.
Today I took a look at my worker (I always look twice a day) and noticed that my GPU had 7 invalid shares, my gpu was working 4 days from OC and never had a problem.

So I went to the stats and… nothing

Maybe it is a bug? I’m lost, I don’t know whether to take it seriously or just ignore it.

Sorry if I made the Topic in a wrong Category.

Thanks for your help!