Originally posted in the BetterDiving issues section.

Breaking tree logs underwater with an axe is inconsistent in breaking speed.
Breaking one log on top of any non-log block has the same speed as above ground (blockBreaking = true), but breaking one log that is below or on top of another log takes around 21 seconds.
Demonstration video: https://streamable.com/hezcg
I figured this was because of the Tree Chopper mod, and it seems to be the case.
I kinda must use that mod because Ore Excavation is unbalanced (excavation speed is independent of tool efficiency and block resistance) and its creator is not concerned with that fact, preferring to tell its users to change the mod themselves. I don't use java so I'm not sure I could do that, so it'd be great if this issue were resolved.

I'm using 1.3.90 of Better Diving and 1.2.4 of Tree Chopper on 1.12.2 Minecraft.