I can now defo say, that latest public winuae causes the issues!
I was smart enough to try an older allready installed version today.
And the snd%meter is constandly blinking in blue and good numbers.
On the latest winuae it is struggeling and flickering from red to yellow and sometimes blue. The meter is going crazy but in the old one its all good.
So 2.3.1 is working flawless here in the sound departmend