Sorry but that is still unbelievable even after thinking about it for a few days and coming back in here again......
There is no way the PF didn't feel the drag, no way the Aircraft wasn't shuddering as the Axles dragged across the Tarmac......
So you say they were on one Engine and therefore didn't notice???? Yeah right!!!
it's bad enough with rubber on the wheels keeping it moving with one Engine around corners let alone keeping it moving with one Engine and all 4 rims dragging.......
If the taxi is rougher than usual, do you just stop?
Absent any instrumentation indication, I'd doubt the crew can be blamed. Seems more like a hole in the Swiss cheese to me, just waiting for a few more to line up correctly...