It wasn't poor track and balance. I was there when they were eventually put into service and the problem was the bifilars.
The aircraft operated in roughly 5 hour sessions but with no shutdowns during that time. Given that the flights normally took 16 minutes there was then 14 (unlogged) minutes of ground running before the next scheduled take-off.
In effect, the bifilar rattled around for twice the logged time and wore out much earlier than anyone had experienced before.
I was a maintainer and I actually thought that the C+ was pretty good considering the crappy environment in which they had to operate. The MRB's would be dripping with black slime at the end of the day: likewise the Arriels were full of black slimy/tarry rubbish when they were opened up for a Bulletin I can't remember the details of, but I do recall the Turbomeca man was horrified.