How to overcome request header field exceeds server limit error?

Question

Apache HTTP Server

I can't figure out what the problem is. Site on Wordpress + woocommerce, stands on a server with centos + apache + nginx for statics. and this error pops up from time to time.

Bad Request
Your browser sent a request that this server could not understand.
Size of a request header field exceeds server limit.

after clearing cookies, it works for a while, but then again. decision vlob type to increase LimitRequestFieldSize Up to 16k or 32k does not help in any way (and it's dangerous as I understand it).
I look in the browser - the size of the cookies if the characters are converted into bytes - there 8kb max is typed.

I do not understand how to debug what is generally wrong to find what creates problems.