My party's slightly split up in XP: two have exactly the same amount, while the third has 1 XP more than them. Then, I finished a dungeon with enough for the third to level-up (to 8), while the other two stayed with exactly 1 XP needed (at the top of level 7). For curiosity, I went to Dungeon of the Lizard Priest, which has a level 7 maximum. Okay, cool, my two level-7 characters should get exactly 1 XP and then everyone would be equal. Nope. They got 2 XP from victory, so now they are level 8 plus 1 XP, while my "too high a level for this adventure" buddy is level 8 plus 0 XP. They got what the rules imply is not allowed. But is this intended? Or should they, in fact, just go up to level 8 plus 0 XP as I expected?
This is a interesting thing to consider, i personally think its fine and hard to abuse in any way since they give so little exp when you are at that limit. But you are definitely correct in asking if this is intended or a oversight because purely logically they really shouldn't pass the max level for gaining exp from the module.
I guess it's a matter of if it's max lvl 7 to be able to gain xp, or not being able to pass lvl 7 from the adventure that's intended . Guess they give the xp as a 2 piece chunk for the module as they were still lvl 7 when it was awarded? Interesting find, wonder if they actually decided on this by intention or if it's a curious side effect. Either ruling sounds ok, but I guess a cap would make most sense?
If they were level 7 when they went in the experience should still be divided and given out even if it puts them over the max level to receive experience because they started at a level that could gain it. This is how almost every game with level dependent experience works.