Tried the new test and compare feature on my channel and it tanked my CTR

I have only been uploading for 7 weeks but consistently getting around 3-8% CTR.

I thought I'd try the test and compare feature for thumbnails....the CTR on this one is 1.7% is this normal?

Its only been there for a day but I darent try again with another video in case that also tanks - If I do decide to take a gamble on trying this with another video will it affect my channel badly?