Change in behavior of wooden pipes and their interaction with coke coal oven occured after upgrade from 7.1.0.0 to 7.2.1.0 on MC 1.5.1. BC build did not change versions.

Coke Oven has a BC pipe to feed wood into the top and second pipe extract charcoal from the oven using a redstone engine on the top left corner of the side using a wooden pipe, and a iron and gate set to produce a redstone signal when items are in inventory.
Setup worked fine under 7.1.0.0 redstone engine would extract charcoal as it was produced. Under 7.2.1.0 wooden pipe is extracting wood blocks as well as charcoal (thus the wood is removed before it is turned into charcoal.)

Issue appears to be a conflict with 1.51 or the last BC version for 1.51 and RC 7.2.1.0. Issue resolved upon server upgrade to 1.5.2.