Hi,
I've seen things like this happen to system entities in the past.
You could try spinning up a 30 day trial (I use
http://demobuilder.cloudapp.net), create a solution containing just the quote & quote product, export it then import to your problem organisation.
Obviously, you'll need to re-do any configuration you may have done to your quote/quote product entities but the above steps should help to 're-set' the associated view if it has somehow become corrupted.
Rob
MCTS. GAP Consulting Ltd. Microsoft Community Contributor Award 2011 & 2013