Still a thing in 1.20.1
Happened to me in 1.20.1 when assaulting an ocean monument, I kept the rockets in my off-hand for the whole raid because shields are useless against guardians. I've had several fireworks go off unintentionally, though my character received little damage due to strong armor.
The textures for chest boats include both the boat and the chest, which can't be textured independently from each other.
Apparently fixed in a later version… though not quite. “Редстоуновый фонарь” is not a correct translation, because “фонарь” is used for translating “lantern”. “Редстоуновая лампа” should be a better variant because it’s distinct from “lantern” just like the English name. Also, it was recently approved on Crowdin and should appear in the upcoming Java update.