Welcome DG 👍I’ve had quite a few of my basses on wall hangers for a number of years and they have all been fine, so I don’t think that’s the problem , it doesn’t sound right that you have to keep adjusting it though
If this is true wear and tear like the seller says then it’s seen some life, very cool bass https://www.ebay.co.uk/itm/Vintage-1963-Fender-Precision-Bass-original-condition-/403347963032?mkcid=16&mkevt=1&_trksid=p2349624.m46890.l49286&mkrid=710-127635-2958-0