You are reading to much into it.
Monarch have two new A321s due next year on lease.
Both Airbus & Boeing as part of there offerings include CEO & NG as interim deliveries until NEO & MAX slots were available.
They are not waiting for problems to be sorted out, just that slots are not available early enough or in numbers wanted.
As for the 2020 statement by me, it was a figure plucked out of the air, deliveries could start a lot earlier but some will be for 2020 and beyond.
