I wonder if it's because of the Lost Children story. Jay struggles to remember his daughter Judy too, he remembered her name when he saw Linda Park in a similar costume, but won't remember her properly until they're reunited in JSA #6. The version of 1940 Helena visited is before the Lost Children were taken away. The 1940s JSA basically had their memories Swiss cheesed!
PG does, yes, and is using them in her Action Comics back-up.