-If a baby bee flies upwards and touches the bottom side of a non-transparent block (stone, logs, dirt, etc) above them, they will take damage.

-They do not take damage if the block above them is transparent (glass, leaves, etc). This leads me to believe it is suffocation damage.

-Only baby bees are affected by this.

I have attached screenshots of an easy setup to reproduce this glitch. Use a spawn egg to spawn many baby bees. The position of the grass and the flower in this setup does not affect the glitch.