Comment 10 for bug 1879479

László Németh committed a patch related to this issue.
It has been pushed to "libreoffice-7-0":

https://git.libreoffice.org/core/commit/e5480bff53f3bd32fc922544f7d1c15854218ffc

tdf#133163 DOCX: export formula cells

It will be available in 7.0.2.

The patch should be included in the daily builds available at
https://dev-builds.libreoffice.org/daily/ in the next 24-48 hours. More
information about daily builds can be found at:
https://wiki.documentfoundation.org/Testing_Daily_Builds

Affected users are encouraged to test the fix and report feedback.