Copper Mine production cycle

it looks like there is a problem with the copper mine production cycle. the production cycle seems to be skipping forward once every cycle.

I counted 9 production cycles in a 9.5 min time span on a mine that normally has 1:54 (upgraded shaft) / 3:24 (normal-shaft) production cycle length. The standard amount of ore per cycle was obtained for those 9 cycles (lvl 2 mine, buffed, 36 ore was obtained in those 9.5 mins).

The mines were self-buffed with aunt-irma's baskets. This skipping occurred with both self and friend buffs. Happened with both upgraded-shaft and normal mines. Happened with both mines discovered by a geo with 30% search time reduction and by a geo with no search time reduction. Happened at different levels of mine (lvl 2 and 3 were tested).

Unbuffed mines were not tested.

Does not seem to be effecting other mines or buildings that I can tell.

Very stange. I'll try and check mine.