I have a Tyger String Eco-45 stringing machine which I got pretty cheap about £240
I have strung about 15 rackets so far and only had this problem once and that was with a Head racket and this was only because it was too tight on the clamps once I cut the strings out ( Mains ) as it was a 2 piece job it went back to original shape and I restrung it after and it was perfectly fine.
I tried it on another 2 Head rackets and both were fine, I tried wooden rackets also they are good.
All I need now is some rubbing alcohol or nail polish remover so I can clean the damn thing and start stringing again!!
Always remember as YuLitle's video help very much and the guy is a legend simple as.
Anyway he explains on one video about mounting, it does not need to be tight at all just tight enough so the racket hardly moves from side to side.