Iron Golem bug
This I remember from D2L, and it affects an iron golem that is made from an item that has an aura. In my case, the aura was meditation from the Insight runeword. What happens is that, after a long play session, perhaps 30 minutes or so, the aura on the iron golem stops working. This happened to me in D2R just now. Previously in D2L all you had to do to get the aura working again is to S&E your current game and start a new game - everything returned to as intended. However, this did not happen to me today in D2R, my Insight iron golem no longer has the aura... period. Even exiting D2R and restarting it does not bring the aura back. The only thing I've not done is restart my computer (going to try that next).
A loss of an Insight polearm is not all that significant. However, some higher end players have made some expensive RW into iron golems. For now I would suggest keeping sessions short.