UTM lines disappearing when printing

I'm trying to print some routes with UTM lines - I like to have a printed map as a backup.

In the browser I can overlay the UTM lines no problem, but when I go to print (export to pdf) some UTM lines disappear eg. only the eastings are shown, the northings are gone.

There is a June 2021 post on this, but the suggested fix (toggling the compass on/off) makes no difference.

I'm using a supported version of Chrome and I've tried clearing the cache.