Yes, please provide a lab report with the experimental evidence that supports the conclusion expressed above.
Well, I made a lumbermill, Plopped it down, gave it water and power, but it wont accept any kind of logs, even vanilla. I watched some videos to make sure I wasn't doing anything wrong but no, that's how its supposed to work. I went into single player and tested as well, with the same results. Its as if the machine is deciding that logs are the wrong kind of input and wont even let you put them in it. Its like putting spawn eggs in a induction furnace, it just doesn't accept them.
Why are you bumping? No point. Anywho, yes, it is broken, we'll see if an update fixes it. Use a TE Sawmill or the Industrial variant for now.