Weird random damages with a wind charge launcher

Steps to Reproduce:
1.Surround yourself with 9 dispensers (the only block where there is no dispenser is above you)
2.Fill each dispenser with a stack of wind charges
3.Connect every dispenser with redstone wires in order to all dispensers will be activated at the same time.
4. Place yourself in the launcher and activate the redstone

Observed Results:
Sometimes you hit a kind of invisible ceiling, your ejection is stopped and you take damage.
I have the impression that the "bug" appears more when chunks are loading.

Expected Results:
You shouldn't take damage and your ejection should be kept.

Video here : https://imgur.com/J9ryFSX
Because the video is too heavy.