Size of a request header field exceeds server limit.

hello,

I am seeing two different errors all the time when using the bulk editor.

We are trying to just update inventory for products. Sometimes it works and other sites it does not. When it works it works great.
but if it fails we are seeing two different errors.

The first being:
“Bad Request
Your browser sent a request that this server could not understand.
Size of a request header field exceeds server limit.”

The second throws an popup error in the browser. Screenshot is attached.
https://www.evernote.com/shard/s16/sh/bb3f791f-bf9d-4dcf-bf64-57629cf78518/E0QcPDM5lt2cq5G7vWtJhLy98CPbMh-ocb5sxfnA9sd_u0VGL_4s-vdxuQ

my users are complaining that they can not get work done.
Please advise.