Shopify Payments Payout Transaction remains in pending state forever

We use the API to load Shopify Payments Transactions.

However we have noticed some strange transactions.

On multiple stores, we’ve noticed that some transactions remain with a payout_status of pending for ever, and they don’t ever seem to get assigned to a payout and paid.

Why would that be?

I can provide specific store and transaction IDs in DM if that helps.

Thank you

Clement