(I originally made a comment on the CurseForge mod page but then later realized here would be a better place to report this.)

The Wooden Excavator is only destroying the middle/targeted block on shovel-compatible ground, despite playing the breaking animation over the entire 3x3 grid area.
All other Excavators (and even Hammers) work as intended, it's just the Wooden Excavator giving trouble.

I'm using the latest mod version (vanillaexcavators-2.0.0-1.16.1)

Should:tm: be fixed in 2.1.0 for 1.16.2. Let me know if the issue persists.

Okay so now a new problem has developed when using the new 2.1.0 update (in 1.16.1).
(Haven't tested 1.16.2, but the mod itself seems to load just fine in 1.16.1)

In creative mode, Wooden Excavators still only break a single block instead of a 3x3 area, and now it doesn't play the breaking animations on the surrounding blocks like it did in the previous version.
But in survival mode, using any Excavator crashes the game.

Survival mode crash report:
crash-2020-09-11_09.43.33-server.txt

Here's a screenshot of the 6 default Excavator types in Creative mode:
Wooden, Stone, Iron, Gold, Diamond, and Netherite.

Seems like an issue with how my library checked for practical effectiveness (like, if the speed of the tool/block is > n, you can break it)... Wooden Excavators were too slow to fit that check, haha. I fixed it making them slightly faster in 2.1.1. Thanks again for the report!