It happens quite often to us that faces of the machinery disapear while the machinery continues to work as expected! (client-sided updates?)
Happens mostly to Transformers, Batboxes, elec. Furnaces.
Furnaces mostly show up as machine blocks.
The bug does not happen to all clients - some no longer see the proper faces while others still see it.
A relog does not seem to fix that issue (unconfirmed)
Forcing a blockupdate by placing blocks next to the compromised block sometimes seems to fix it.
(Sry, cant give more info now - that was a 3am testing round)
Seems like the texture updating of machines is a bit off in SMP
And here I was, thinking it was just me
Had same issue, though relogging usually fixed it temporaryly. Nothing gamebreaking, though.
Well, not a gamebreaker but its more than a slight nuisance when you try to find out to which direction your MFE/MFSU or such are pointing and click the face that dismantles it... woops, millions of EU gone... =/
For me, reloading does not fix it. My machines have no faces when in a row so I have no idea what they are.
My machines' face flicker from time to time, not much of a problem, but i do have the mfsu, bat-box, etc. problem... As one said, loosing millions of energy because one thought that it wasnt oriented the right way... Doesnt break the game, but you have to remember how it was XD