I've discovered a bug involving the mechanical press that is able to be reproduced, and will instantly hardcrash a world and corrupt it, making it unable to be re-opened unless you have a backup.
The procedure to produce the bug is simple - Simply have a setup like the one below:

(The mechanical piston is sticky - although it probably doesn't matter - and has one extension pole behind it.)

Then drop something into the basin that is packable (like 9 iron ingots to turn into a block). Once the mechanical press starts moving down, turn the crank to move the press to the andesite casing. When the press reaches the bottom, the game crashes, and the world cannot be reopened without reverting to a backup.

Here are the crash reports related to my testing of that exact setup (The first is the initial crash, the second is attempting to start the world again):
crash-2021-11-21_02.19.50-server.txt
crash-2021-11-21_02.21.43-server.txt

The only apparent fix other than reverting to a backup of the world appears to be to remove the press from the world manually using an external world modification program like Amulet. (Thank god, I would have been real sad to lose the survival world where I discovered this...)