Open any database, for example https://bugs.documentfoundation.org/attachment.cgi?id=167470 . Open the form for editing. Try to set the default value for any control except controls, which should contain text. Won't work in LO 7.0.3.1, works well in LO 6.4.6.2 and also in LO 7.1.0.0 Alpha 1+ from 2020-11-21. See also https://bugs.documentfoundation.org/show_bug.cgi?id=138404#c2
Seems this is a duplicate of bug 138217. I will set it to duplicate. *** This bug has been marked as a duplicate of bug 138217 ***