When creating an upwards facing dripstone that has at least 2 blocks, and the edge of the bottom block is far from the edge of the block underneath it, falling onto it doesn't deal fall damage. This will make more sense in the steps to reproduce.
How to reproduce:
1. Create an upwards facing dripstone that consists of at least 2 dripstones.
2. The dripstone block at the bottom must be pretty far from the edge of the block it's on. I don't know how far it needs to be but I know it's at least 3-4 pixels inwards from the edge of the block below it.
3. Put your player on top of the bottom dripstone block. So the player is on the edge of the bottom dripstone.
4. fly upwards a little bit in creative mode, then switch to survival and fall down. You should fall onto the bottom dripstone and take no damage.
Video if the steps are confusing: https://youtu.be/f25Eauigudw