The instruction to stop/start works is a compensation event under 60.1 (4) as you have said. If the reason why the instruction was given is due to a fault by the Contractor then the PM can state this in the instruction.
It looks like your contract has been amended to include the words ‘actions of the Contractor’, although you would need to be certain that the Contractor has actually taken some form of action, as this wouldn’t necessarily include ‘inaction’, depending on the wording. You say the Contractor owns the risk but haven’t said whether any associated events or actions have actually occurred.
I would suggest notifying an early warning and discussing your proposed action before an instruction is given. Any actions consequent to the early warning meeting may negate the need for an instruction.