Indesign 20.3.1 x64 release.

Attached is the Indesign file. Both frames are identical, except for the topmost has one non-breaking space and the bottommost has a regular space instead. The export from the top frame produces the buggy RTF (a screenshot of the glitch location is attached), while the bottom one is ok. If we put any non-breaking space there - it will fail as well.
The bug was reported as font-dependent as well, i.e. the text set in Arial may have the bug while the text set in Minion Pro may not have it.