Dynamics is certainly a factor, I cant quite reproduce your paint stroke but....
Basic Dynamics does have an opacity and fade setting.
Some time in the past you have changed default toolbox settings Force is 50 / Fade length is 100 / Repeat is None.
First thing to do is change the Dynamics from Basic to Dynamics Off
Basic Dynamics does have an opacity and fade setting.
Some time in the past you have changed default toolbox settings Force is 50 / Fade length is 100 / Repeat is None.
First thing to do is change the Dynamics from Basic to Dynamics Off