Assume a traveler holds two passports from two different countries. Does the passport they use to enter and leave a country sometimes determine which passport they must use when entering the next country, or is that always independent? The holder of these passports is not citizen of either country.
I have two passports/nationalities. How do I use them when I travel? does not address my question, they just say "B passport" without specifying it (i.e. they don't say if when entering country B one can always use the passport used to enter and leave a country A, assuming both nationalities are granted entry of course).