What the policy update did is extend the ticket validity, ie you don't lose the value on Jan 1, 2023. What it did not do is extend Bulletin 6 rebooking dates which is still Dec 31, 2022. This is the fly by date but you might find a careless agent who interprets it as a book by date (see above for example).
Also Etiene is correct in saying that "parked" tickets have less chance now because 1) the policy is almost 3 yrs old and 2) any non-parked ticket (ie with flights in it) have been reissued so many times due to sched changes etc that they will simply not bother to track down what's what and just keep doing even exchanges as long as classes match. With a parked ticket they do have to look at rules to know what to do with it in the first place.