Cloudflare adding wrong Content-Length to some users

A user on my website started to get net::ERR_CONTENT_LENGTH_MISMATCH.
Their request to a specific page returns an additional header Content-Length, which isn’t showing up for me.
I’m pretty sure my server isn’t adding it, and I’m not adding it code side, so I’ll guess its getting added on CF side.
It says the content length is 175810, but the length seems to be less than that (175746).
According to: node.js - How to get net::ERR CONTENT LENGTH MISMATCH in Chrome using express - Stack Overflow

[…] if you send less data, and make sure that the connection gets closed server-side […], you can trigger net::ERR_CONTENT_LENGTH_MISMATCH

So far we’ve had 3 users with this issue, and we’ve not able to figure out the problem.
I tried to remove the header “Content-Length” from Rewrite Rules, but its not allowed.