In my experience this happens every month for the 1-3 day period between when the month’s pledges START to be charged to when all the charges clear the various credit cards/banks.
It’s always a little bit confusing.
The way I understand it is, if you had $500 in pledges but then a $50 pledge declined on someone’s card, your page would/should show $450 - to accurately reflect what you actually make this month, even though $500 was pledged. But during the period when cards start getting charged, the charges don’t all clear immediately, and since Patreon doesn’t KNOW if you’ll have that money, the display widget acts as if you don’t.
Patreon Product team: I’ve said this before in product feedback on the site itself, but I’d love to see this fixed in some way that gave a little transparency into the process for both patrons and creators. Here’s how I would fix it:

Except I’d get a real copywriter to write something for that info tip that makes more sense.