I did some searching and found a few instances of this that were resolved with software updates, but that was in 12.0 and 12.1 versions, so 12.6 should be okay. I see a later instance where an RMA was requested for the blade and no trouble was found at the repair facility. It's hard for me to say with certainty what caused this, but you'll want to monitor for sure. Keep in mind that you're dealing with 11+ year old equipment :)