I'm using the latest version of Forestry 1.12.2.
The problem is that a multi-farm of regular oaks and apple oaks, and most likely any other, that deals with humus and dirt, when it breaks sand, does not throw it into the farm hatch. That is, sand is not produced as a product by the farm.
Is this how it should be? As far as I remember, sand used to be mined by a multi-farm.
This makes it difficult to craft bog soil, which is needed for the peat engines that power the farm. Thus, cyclical production does not work.

I changed it to the recommended stable version of Forestry 1.12.2-5.8.2.387 and everything worked