Just want to throw my confirmation in that changing useRDTSC in the game profile worked for me. In my case I was having issues with DuckTales Remasterd through LB on Cemu 1.15. Although since my Cemu default is set to have it set to true, I had to change the game profile to false. Odd that I can launch it outside of LB without issue before this though.
[General]
useRDTSC = false