As ElphabaGoodman pointed out, there are a handful of shows that have remained on sale throughout the pandemic. Until recently, they were on sale beginning the week of 5/31; now, they're on sale beginning the week of 8/2. Rather than a sign that these shows will be returning around this time, this more so seems to be an indication that the date for offering refunds or exchanges has again been extended (from 5/30 to 8/1).
I'm wondering if we'll soon see another press release/announcement from the Broadway League about a new suspension of performances, or if we've instead reached a point where it's now going to be up to individual productions to begin announcing their plans for reopening. If it's the latter, I suspect we'll start to learn more around Memorial Day, as the "current" deadline lapses and we have a clearer picture of the state of the pandemic, vaccination, necessary safety protocols, etc.