Minecolonies version
minecolonies-universal-1.12.2-0.8.7415
forge1.12.2-14.23.1.2555
OptiFine_1.12.2_HD_U_C8
no other mod

info:
map test creative solo
/ mc colonies rsResetAll at every update

Expected behavior
hollow tunel, harvesting ore, mouth holes, climbing structure

Actual behavior
the miner recorks the holes and builds only with dirt (see do fail)

before on my server under construction (stop in July waiting for maj 1.13, very modified), he used the cobblestone (version: minecolonies-universal-1.11.2-0.8.2689)
now he claims only dirt and ignores the cobblestone (2 double chest cobblestone in warehouse)

Steps to reproduce the problem
remove dirt in warehouse and miner inventory

retest:
I just made a new map with miner level 5.
during the descent I help the miner and empty his inventory in dirt.
no problem cobblestone used for schematic "minerMainshaft"
then first schematic "minerx2top" tunel height 7 of the world

I observed in gamemode 3:
1- fill the air with cobblestone
2- dig and harvest ore
3- barrier application and dirt request to plug the holes
4- finished by laying board and torch

continuing with the other schematics, it is similar

conclusion:
before the construction it recorks air with cobblestone,
but not during it needs dirt

Can confirm this this too. I notice to much cobblestone in the warehouse, and the miners always waiting for dirt from the dmans

should be fixed now