when a zombie jumps into a boat with a villager, instead of the villager converting into a zombie villager, it simply dies. The same thing happens if the villager is in a minecart, and a zombie (not in a minecart) kills it.
MCPE-93183
Villagers not converting to zombies when in boat or minecart
Resolved
Invalid
0
What difficulty is your game set to?
On easy mode, villagers can never be turned into zombie villagers, and on normal mode, there is only a 50% chance that the villager will become a zombie villager.