Are you perhaps using some Office installation in English as well? The reason I ask is that there are also three built-in caption labels, whose names are different in different language versions of Word. This may be relevant to your situation (at least if you move files between, say, German and English Word).

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Stefan Blom
Microsoft Word MVP

Microsoft 365 apps for business
Windows 11 Professional

Yes, the basic Word installation is German. Everybody who is under my guidance, must work in English. Every time they introduce a new user or a new machine arrives, I have to create captions for Figures (German -> Abbildung) and Tables (German -> Tabelle), but this is under control. We don't use Equation (German -> Gleichung). This is one of the many poor programming techniques of MS. I have seen a document written/formatted using an English Word read into a German Word which then destroyed all the cross referencing and captions. The culprit could not remember exactly what he did and I was unable to reproduce it. Simply wasted a day correcting the document. You have to accept that Microsoft does not understand that you might be wanting work in two (or more) languages, does not notice you have installed the language pack to make it talk to you in a different language from the operating system, and add captions accordingly. After many years experience, I recommend never mixing Windows OS with programs written & working in a different language. You might be lucky, if the programmer was good, but it can cause problems.