Unusual WooCommerce hook activation?

So three customers paid using PayPal Plus (the only option available in this shop anyway), but for yet unknown reasons the payment failed and these orders are listed as cancelled. This happens sometimes.

However, what is unusual is how WooCommerce is triggered by the payment gateway plugin,
according to the order detail page:
First, the stock is decreased.
Then, 68 minutes later, the stock is increased again.
Also, 68 minutes later, also a message/state is added that the unpaid order has been cancelled because of timeout: Unbezahlte Bestellung abgebrochen – Zeitlimit erreicht. Status der Bestellung von Zahlung ausstehend auf Storniert/Abgebrochen ge?ndert..
The link to the digital good also was sent to the user despite the payment have failed, although it wasn’t usable as it wasn’t valid.