Any scenarios off the top of your head? For example, RJ's become landing weight restricted when the leg is really short and the wx is bad enough that theyre carrying extra alternate fuel.

However, I cannot for the life of me explain how an a320 gets weight restricted out of PHL, going on a 4+30 flight. It can't possibly be togw restricted at sea level with a 10,000ft+ rwy on a cold day, and it cant possibly be landing weight restricted because its burning enough fuel on a long leg. Thoughts?