Enderman spawn rates too low in bedrock 1.16.201

I have recently just created an enderman/XP farm and noticed that the spawn rates were too low. I usually used to get 80-100 in 1 minute in the earlier versions of mc but now I get from 4 up to 10 in a couple of minutes. This has affected the game a lot and now I am not able to gain as much XP as I should, please fix this asap.