I absorbed 2 dragon souls in the beginning but now I can't...killed 3 and it goes thru the absorb effect but no souls in inventory. Any Ideas?

I have the game modded from the beginning and nothing added since the the first 2 kills. I do have the unofficial patch installed

This is the PC version

Have you started the Dragonborn questline? Once you reach a certain point in the questline, the souls you absorb can be stolen until you complete it.