I'm have a very similar (active) issue with capital one. Transferred 1,000 miles and 2,000 miles no issues on 06/16/23 (Friday) around 7 AM to Flying Blue. Transfer was under 30 minutes to show up in account. Received no emails from Capital One.

Tried transferring over 500K to Flying Blue around 2 PM on 06/16/23 (Friday)

As of this posting (Sunday) 43 hours later still not showing up. Shows as "pending" with Capital One

My account is not locked with capital one. Monday is a holiday so curious to see what happens.