Relates to MCPE-43759
The smallest possible size in Minecraft is 0, with support for sizes ranging from 0 to 127. Slimes also have a minimum size of 0. It wouldn't be logical for phantoms to spawn at size 1. This is a feature request.
This parity discrepancy probably arose prior to the Buzzy Bees update, rendering this issue potentially invalid. The addition of tropical fish mobs during the aquatic update doesn't necessarily imply that the parity issue emerged at the same time. It could have been introduced later, necessitating further testing to determine the version.
Relates to MC-197028. Perhaps Mojang will rewrite their entity hitbox code at some stage. Presently, all entities are confined to cuboid hitboxes. Introducing rotation and other adjustments to hitboxes would increase programming complexity.
This bug report describes being propelled upward upon hitting non-living entities in general. MC-269954 pertains to this occurring while in flight. Although related, these issues are not identical. The observation that hitting non-living entities propels you upward, even during flight (unlike living entities), suggests an intentional addition of this mechanic.
Please update the summary to: "You can use items in your offhand slot if you have food in your main hand but your hunger bar is full" This applies to any item with right-click actions in the offhand, not just blocks.