Since 24w44a, when a TNT minecart is hit by a blaze fireball, it explodes instantly; previously the random delay of 0-1.9 seconds applied. The new behavior is consistent with flaming arrows being able to instantly detonate TNT minecarts, so it could very well be intended, but it wasn't a documented change so I'm reporting it just in case.

To reproduce

1. Ensure no important builds are nearby

2. /summon minecraft:tnt_minecart

3. Fly up a couple blocks to ensure the fireball hits the minecart and not you or the ground (see also MC-125936)

4. /summon minecraft:small_fireball ~ ~-1 ~ {Motion:[0d,-0.5d,0d]}

Discovered while testing MC-254356 (it's fixed now, yay!).