The first reopen-review was clearly triggered by the immediately preceding edit. What triggered the 2nd review, five days later?
Unless you are a moderator, not all sources of triggers are visible in the timeline.
Reopen reviews can also be triggered by someone casting a re-open vote directly on the post. Since that’s a vote to reopen these are not shown in the timeline for anyone below moderator level. Someone almost certainly tried to reopen that post directly from the post itself here.
There is an open feature request to add daily summaries of close and reopen vote counts to the timeline.