Meta Graph Api - Missing Previous Token For Previous Page

I'm using Meta Graph Api Explorer to test the Meta Ads API.

And the results look like this:

Request For First Page

When I add the after token into the request as a parameter, it doesn't return the token for the previous page:

Request For Second Page

here's the URL endpoint:

ads_archive?ad_reached_countries=['GE']&search_terms="A"&after= c2NyYXBpbmdfY3Vyc29yOk1UY3pNek0yTURRd01EbzRNakUyTnpZAMU9UTXpNVFl6T1RNPQZDZD