"~NH" in Sinhalese Pali Orthography

I note that modern Sinhalese uniformly supplants the combination "~nh"
with ".nh" --I am not sure if this rule is phonetic or orthographic,
but the retroflex .n replaces the ~n whenever the latter is ligatured
to h.  Possibly this is not the only instance.

My question is how this impacts Pali orthography.

Do Sinhalese Pali MS *or* printed editions substitute a retroflex ".n"
into the combination "~nh" ... or not?

I would appreciate any opinions on this matter; it is difficult for me
to judge, as I have never consciously "searched" for a context in
which ~n/.n could be clearly seen as an error (super-imposed by modern
Sinhalese typesetting).

E.M.