The small rock crusher has to be unlocked by "gravel_mining_1" research. But the large vanilla gravel processing plant is still available without any research.

That's not a bug, the small rock crusher is there because the creator want it to be there.

I meant that some other vanilla factories (which are larger than smalled mod buildings) need some "research", but the vanilla gravel processing plant doesn't.

EDIT: To clarify, I thought this was stange:

1. rock crusher: small, low production. But needs some "research" to be built. OK.
   
2. standard gravel processing plant: bigger, higher production. And can be built immediately, no research needed. I would expect it to need at least same tech level as the rock crusher (or even higher - up to you to decide, of course).

Tried to disable the mod to do some experiments.
Followed the directions to remove update.bat file from the launch options.
Can't seem to get rid of it.
Any ideas?

Originally posted by RedDog:

Tried to disable the mod to do some experiments.
Followed the directions to remove update.bat file from the launch options.
Can't seem to get rid of it.
Any ideas?

You have to fix the game's research directory which contains the research tree used by the game. I believe that the game file check in Steam should be able to replace the research tree with vanilla tree.