The Bug
Mobs riding large entities, such as a zombie riding a sniffer, can still attack players who are completely above the vehicle and out-of-range of the passenger.
How to reproduce
Summon a zombie and a sniffer, then execute
/ride @e[type=zombie,limit=1] mount @e[type=sniffer,limit=1]Build up 3 blocks from the sniffer's position
Check the range the zombie can attack you from
Attachments
Comments 4
This is intended as per https://www.minecraft.net/en-us/article/minecraft-snapshot-23w33a
The mount of a mob now extends its horisontal reach to match mounts hitbox.
In your video the player doesn't seem to be completely above the horizontal mob range though, so the rider wasn't exactly out-of-range but with an increased reach because the sniffer has a wider hitbox, and this can be reproduced with monsters riding interaction entities with large width.
[media]One could argue this might or not be used as a feature for mobs with custom horizontal range, but could be considered a bug, so i can only confirm this case.