Numbering and bullets in Word docs keep disappearing

I've been setting my docs up according to Shauna's guide for a decade or more and they will work fine (more or less) in a local environment, but as soon as you introduce SharePoint to the mix and multiple authors it all goes haywire. By now I have a great set of macros that are available in a custom toolbar and the templates themselves, which is why I keep the template on SharePoint too, that will essentially do some version of a "tick/untick".

I have no technical knowledge of the MS Word code but I feel like the co-authoring stuff was built for the online version (which might be entirely new code?) and somehow shoe-horned into the desktop app, and it just doesn't play well with the ancient list style code. The documents can behave themselves for a while, but for instance just before review time now I have 7 people in an 80-page document and it's absolutely blown up: refreshing styles won't fix everything. It won't be until I get everyone else out of the document and run it that it will all settle down.

List styles seem pretty flaky to begin with: I've often had the situation where I've gone in to edit the numbering or indents of the styles in a list style and when I press ok the list style loses all the linked paragraph styles, so I have to go back in and assign them all again.