An alternate Universe Jennifer from Earth 2 was shown prominently in this episode, except Earth-2 was erased at the end of Arrow S 8 E 1 Starling City, while this episode happens shortly before or shortly after Crisis starts. And for both Earth 1 and Earth 2 Jennifer, they both get erased by crisis, though Earth-1 is still around and as mentioned Earth-2 was already erased.
Attempting to tie in with the Arrowverse led to several problems, as what it refers to as "Earth One" and "Earth Two" cannot be the same worlds that the other Arrowverse shows refer to by those terms: The ASA may have strong pull on Black Lightning's Earth, but the idea that they could get away with anything they're doing on the same Earth-1 that has an Argus, let alone numerous superheroes, doesn't sound right.