I found 3 "bugs" while trying to make a vine farm.

For all the following exemple, a storage interface is used to put shears in the contraption and to take vines out. I also used redstone contacts linking to a power latch to make the contraption go back and forth. Deployers are set up with a filter allowing shears ignoring nbt data.

1. The first one is that in the following configuration, the rightmost group of deployers will not interact with the vines. This only happen when the contraption is moved via minecart/assembler.
   
   
   

2. The second one is that when the exact same contraption is moved by a gantry (and sometimes mechanical pistons), the shears seem to disapear when the contraption switches direction or if the contraption is stopped. The shears then cannot be found on the ground, on chests on the contraption or in the output of the contraption. See video below
   https://youtu.be/Tuh-kLkl96Y

3. Deployers attached to a mechanical bearing powered by a windmill won't interact with vines at all.

I also re-did all tests with only the Create mod, same behavior.

This issue has been marked as stale because it has been inactive for 3 weeks. It will be closed if it remains inactive for another 3 weeks.

This issue has been closed since it has been inactive for 3 weeks since it was marked as stale.

On the other hand, this setup works flawlessly. The only differences are the size and orientation..

Edit : Well, just tested and it works just as well in N/S orientation. All out of idea.
Here is the world download if it helps :
2021-04-19_18-42-40_Mod Test.zip