The problem seems to have been introduced in Motif 2.3.4. I built (Open)Motif 2.3.3 and the numeric keypad works in nedit. I also tried downloading and installing upstream's Motif 2.3.4-1 binary package [1] and only the 5 key on the numeric pad works in nedit.
Unfortunately, upstream's bug tracker [2] is currently down so I cannot check if this issue has been reported already. [1] https://motif.ics.com/motif/downloads [2] http://bugs.motifzone.net/
