the reason on 2019 is the reason she came here on J-1

the reasons for waiver can be something unrelated to the programme she was on. she can apply waiver based on the reason u just mentioned. it's a good reason if she got the recommendation letter. but this does take a little longer to get the No-Objection letter(embassy has to check out everything and her background also make sure there were no Chinese goverment fundings).
one other possible reason for waiver is "marriage to US citizen", it's a quicker and little easier way to get No-Objection letter. she has to come up with marriage license and her hu*****and's prove of citizenship.