Iol lens shifts after surgery?

Rare. Iol lens shifts occur rarely after cataract surgery if performed correctly and if no complication is encountered. History of trauma, complicated surgery, pseudoexfoliation syndrome, and other issues can increase this risk.
Sometimes. Most iol's remain in a stable place and position after cataract surgery. Some might shift a little in position due to the biology of healing. Occasionally there is a big shift which might require repositioning surgery.