[arnsholt]

It’s been ages since I did Sanskrit last, but wouldn’t sam-cika typically have the m realized as an anusvara rather than ñ?

[sieve]

Not unless it precedes a classless letter or it is actually "m."

All nasals becoming anusvaras is something Hindi/Marathi and other languages using the Devanagari script do. Sanskrit uses the specific form of the nasal when available.