Obsidian transport pipes are not picking up items (at all) when connected to an engine (sterling or combustion). Functions as normal/expected with redstone engines.
It appears that the pipe is "connecting" to the engine, which I don't believe should be happening. Pipe functions as expected with no engine connected (picks up items dropped directly on the pipe), but once an engine is attached, it won't even pick up items thrown directly on top of the pipe.

Closing...
sigh I didn't see the new builds today from CovertJaguar where connection rules were updated... Compiled the new sources and everything was good.