Screws getting loose on ADM Rexon-X?

I mounted my MK 4 in ADM Recon X mount a few weeks ago and shot it once. I thought the screws were on tight, until I took it to the range yesterday. After establishing 100 yard zero, I decided to check on the screws. All of them were loose! And this is despite me using blue locktite. I think they were not tightened down properly at the beginning as the most likely explanation. Having tightened down the screws, fired a few groups and tightened them again, I was satisfied. However, I noticed small notches in the middle of screw holes - see photo. I didn’t pay attention before mounting so I am not sure if that’s normal. Could I have overtightened them? I used allen wrench with the long arm. Also, what damage is possible to the scope tube from overtightening?

Photo:
Notches above screw holes

they ship them with oil on them
did you remove all the oil prior to applying loctite?

I have several of their mounts and never had a problem with bolts coming loose
and I don;'t use the loctite either