Resaving test document without compatibility mode resolves the issue.
Resaving Calibre demo document in compatibility mode causes the issue appears.
Following detection method described on
https://www.howtogeek.com/256269/wha...rosoft-office/, the compatibility mode versions of tested documents are the same ("Word 97-2003"). There must be some additional difference.
Anyway thank You for your assistence. The problem is quite specific and not primarily caused by Calibre.