There is an updated pull request by intr-cx against master on the mblaze repository

https://github.com/intr-cx/mblaze master
https://github.com/leahneukirchen/mblaze/pull/246

Ignore fake message IDs set by Protonmail
Proton-bridge injects fake message IDs suffixed by `protonmail.internalid` into References headers. This causes mthread to mess up and introduce a bunch of noise from supposedly missing emails. 

I know this isn't the cleanest solution and it is a bit of a niche problem, but I dug around a bit and [mu](https://github.com/djcb/mu/blob/5409c2cd8760fa9909feffd51159fecaee8fb04e/lib/message/mu-mime-object.cc#L432) for example works around it in a similar fashion.

A patch file from https://github.com/leahneukirchen/mblaze/pull/246.patch is attached