I have heard of this effect but first time managed to catch it on photo.
Montes Jura (Jura Mountains) the bright rim that looks like it doesn't belong to the Moon. It is an effect when the Sun is rising at this part of the Moon and because of the bigger elevation than the local surroundings the top part of Jura mountains are lid first. The highest elevation above the local crater Sinus Iridum (Bay of Rainbows) is around 4700meters.
It is really an interesting feature too see and look for on the Moon, but just when this part is on the terminator.