Maybe because the A320neos haven't been parked for a year? Just a guess.

I incline to see a link behind the difference with the governing authority, i. e. FAA for B. and EASA for A.

That document linked above states that the product has been withdrawn from the market in March, that it no longer poses a threat after multiple refueling cycles and that 75 MAX are expected to be affected.
So to answer my own question partly, it's deemed a:
- non issue for previously treated but operated aircraft due to dilution (eg. 787, neo)
- non issue for COVID grounded aircraft due to product (non) availability
- issue for a certain type with 75 treated aircraft sitting on the ground for ages.

Except that if it is an engine issue, and not an aircraft one, there is only one governing authority, which is EASA for the CFMI Leap Engines.

.

More 737 woes!
 

FAA Issues Emergency Directive on 2000 737NG and Classic planes: Link here

It's a shame the mods have seen fit to move this post (which merits a thread on its own) and tack in onto the end of a completely unrelated thread. :ugh:

Wondered where it had gone, Finally tracked it down to here. Not sure why it got moved, but I'm sure the mods have their reasons.

I suspect they didn't read the AD and don't recognize it's a completely separate issue. Different affected models, different system, different technical problem. It is not a Max issue. The only common threads are storage being a factor and the potential for dual engine power loss.

FWIW:
(not as a mod)
Recent report regarding an A321 that ran into a similar issue