[2021] charcoal kiln stops working due to full storage rather than delivering to in-range warehouse

this is VERY weird
i have an arctic island with 2 charcoal kilns, each in range of the 2 heaters on the island, and well as the 1 warehouse
1 kiln is modified via lodge to work at 170%, thus there is a surplus of coal on the island; the global island storage for coal is not full
rather than delivering excess to the warehouse (which is reachable for it), the kiln decides to stop working due to full storage

i thought it might be path-finding bug, so i created a new game and duplicated the setup of the island: everything worked as expected
moved the kiln away from the road and then back into its original location: did not help
save/reload: did not help
destroyed the kiln and recreated a new one in the exact same place: problem fixed (!)
here is the savegame: https://www38.zippyshare.com/v/ObZAPNVs/file.html

edit:
deleting the road (yellow) and instead connecting the kiln where marked in blue will also fix
which is why i originally thought this is path-finding
BUT returning the road back to the yellow (current) location will recreate the problem
(this just masks the problem rather than solve it)