Yes, we have that problem with the engines shutting down as well. Ours do it at any speed, though. Ours were shipped via flatbed down to Disney, for the exact reason that too many were breaking down when the first batch was driven. I remember one night, I had one with only 300 miles on it. First day in service. Died at the All-Star gate. Another with only 4,000 blew a turbo. Yet another cracked a rear axle at 7,000.
Thankfully, they're leased, and will be gone soon. (Who would have thought the 25 year old RTS would outlive the Nova?? LOL)