The bug

When you have a nogravity boat (on level for example 65 and a block on level 64), and you ride that boat into the block (reproduced on various speeds), the boat sometimes (like 10% - 30%, does it more on higher speeds) briefly glitches out, and views the block below it as a barrier - however when you stop ramming into it - it lets you go through.
The following warning is logged:

Boat moved wrongly!

And than the JVM crashed (possibly unrelated): https://pastebin.com/raw/Ep2mtycL

How to reproduce

1. /fill ~-1 ~ ~2 ~2 ~ ~5 blue_ice
   

2. /fill ~ ~ ~3 ~1 ~ ~4 air
   

3. /execute align xyz run summon boat ~1 ~1 ~2.5 {NoGravity:1b}
   

4. Drive accross the ice multiple times
   A few times the boat will act as if it collided