Some would say that, sure, but they’re making a stretch not supported by any actual custom or convention.
The caretaker convention applies when the writ of election has dropped. The Privy Council guide he quotes is here:
Guidelines on the conduct of Ministers, Ministers of State, exempt staff and public servants during an election - Canada.ca
As we can see from actually looking at it, the guide itself specifically situates itself in the context of the dissolution of Parliament and an election having been called. It’s noteworthy that Hopper quotes it in part but doesn’t provide a link for people to assess it themselves.
There is no convention standing in the way of what the government is currently doing. As soon as the writ drops, then it will apply. While ‘it could be argued’ that the convention should be extended in a new and novel way, that would be nothing more than a statement of opinion. Carney is ignoring the Caretaker convention in the same way that I, when driving home from work in Ontario, ignore the speed limit in Manitoba. It’s a simple matter of it doesn’t apply to the circumstances.