Bitrate jumping on stream

[exam1ple]

Hello guys i have big problem with streaming beacuse my bitrate in right corner obs jumping i set it to 13k but its going to 16k,10k and spoil my stream quality how to fix it ? im using nvenc and my upload is 50+

 

[exam1ple]

for example when i set it to lower 8k its droping around 9,7,10,11