Word suddenly behaving crazy for no reason

[zed86]

Hello everyone,

Over the past years I encountered a problem I have not tackled because it seems to solve itself after some weeks, but this time it's driving me crazy, and I can't wait that long. I use Word everyday and everything works a certain way, the way I want, then suddenly it starts behaving differently, e.g. :
- displaying Thumbails by default instead of Document Map when opening a document
- pasting stuff from internet in a huge font size instead of the usual "normal" way
- putting many random sentences in my documents' paragraphs as Titles of Level 1 in my Table of Contents, although when I select the text, it still shows as "Normal" or "No spacing" in the Style panel
etc.

It does that for a couple of days/weeks, then not anymore for a couple of weeks/months.

Any idea about the reason, and how to control this?

PS: I’m not interested in individual fixes to modify the behavior of Word for the examples given, I know that already: I would like to understand what may trigger this occasional temporary chaos after months of decent behavior, so I don't need to change the default copy-paste options and all.

If this info helps : I modified a long time ago the Normal.dot file so that new documents load with my custom Styles set, but that's about it.