It seems like your X and Y belts are too loose. This causes them to skip gear teeth sometimes, making your printer start printing at an X/Y offset from where it was before.
To test if this is the case, print slower (fast print speeds increase the belt jerk, which increases the chance your belt will skip teeth). If your print turns out OK, then this is your problem.
If this is your problem, then either cut your belt shorter or print some belt tensioners (slowly) to tighten your belts. Search thingiverse for “anet tensioner” to find X and Y tensioners.