Here's the relevant passage translated through google:
FIA-start mode overrides any steering wheel commands
That's right, while wrong. No matter what button Rosberg had pressed at this stage, it would not help. Therefore, it is also misleading when Hamilton claims he has switched to curve 3 in the race mode, while Rosberg was on the road in the starting mode. This is simply not possible.The transition into the race mode is automatic.
For the first 90 seconds after the start of the FIA-start mode overrides all other programs.Thus, the push-to-pass could not function.Nevertheless, Rosberg could not help it. Or a conscious thing. The power loss must have been a software error. Whether it was caused by the formation lap because Rosberg had driven in the starting mode accidentally, it can be clarified by the Mercedes engineers only after accurate data analysis in the factory.