I saw same problem on astropad1.3.5
clip studio paint ex 1.5.2
We will keep improving the pressure rendering.
I am not super familiar with Manga Studio, can you tell me a bit more how you configured the brush settings?
Sadly I could tell you even up to today , even for astropad studio , this problem still exists.
though it was muh better comapred to the past , it still happens in a 1/100 chance randomly, and will frequently happen when OBS live streaming is turned on.
here is my latest post related to this matter:
Clip Studio Paint x OBS Streaming Issue