CECs are easier to process, and PNP are fewer in quantity, so it makes sense what IRCC is doing.
Remember that most countries are shut down, IRCC are not dumb, they know based on trends where most FSW candidates live and come from, and they know they will struggle to get their documents together in the next few months, even in 90 days.
So they are waiting for the situation to improve first before reissuing ITAs for them.
I would not read too much into it, it's being done for practical reasons relating to the current situation, not because of some long term shift taking place.