Speaking for Linux, the keypad behaviour is slightly "erratic", some times it behaves normally, i.e it respects the "block num" status, some times not, I haven't found why and when it appears, at least on my Devuan "Debian" machines, (two different machine, runnig the same distribution).
Some quick search I've done some time ago gave no result in such behaviour, but some time ago Mono was not so widespread, but hoping in some future investigations, as in Mono things are moving at different speeds, the part that interest Microsoft are ironed out quickly, other part are labelled "community efforts" or similar and left at the community "good wills" to iron them out.
Regards
Carlo D.