We have found a difference between Aspose.Words for .Net version 14.6 and 21.5.
With the attached file, in 14.6 AcceptAllRevisions keeps the styling but in 21.5 the style is removed. This is most obvious on page 16 where the subscript style is lost on Cmax/Cmin, but I can see Bold/Italic has also been lost in some places.
If I do “Accept all changes” in Word 2019 (2112) the problem goes away. Likewise if I save it to docx. Likewise if I copy the problematic text into a new file. So to me it looks like the Track changes feature is the root cause.
This is a customer file so I cannot share it here I think but if I can share it privately to the support team that would be ok.
I have tried to reproduce this issue with other files to no avail…