Watching the launch of Optimus, it's clear they launch stern first, and it's also clear that the 85 has rotated 180 deg to it's position in the bottom. I.e. it is stern to the ramp rather than bow to the ramp as it was initially launched. This suggest to me that it had fully floated free of the dollies before rolling.
Although I completely agree with the potential for the tricycle dolly system to induce a roll as a boat is launched, it would appear this one survived at least that part of it's journey.
Sooooo, to keep the arm chair warm, I'd like to elaborate on a theory....
Most big disasters are a combination of failures, not a single failure. I would postulate that:
1) As BandB suggests, there was a generous amount of hubris is this build, resulting in a design that relied on ballasting more than previous builds.
2) A boat that pushed the limits of the transport system, or perhaps completely overloaded it.
3) A boat that was not ballasted, or lightly ballasted, to keep weight down because they knew they were pushing the capacity of the transport system.
Put those three things together, and it's a big Oh Sh&#t.