I still experience the same Matrix bugs as I did years ago... When you setup a new client, it can take 24h for the content to get decrypted after you verify that client...
Verification is nothing to do with decryption - verification is how you confirm that you're really speaking to the person you think you're speaking to.
What you're describing sounds like a plain old encryption bug, although I'm very surprised you're still hitting it, given encryption in Matrix is pretty stable these days. If you can file a bug on github.com/vector-im/element-web/issues (or element-ios or element-android, depending on what platform you're using) with the full details or reproduction steps, I'll take a look.
Also, there's 3 messages that I keep trying to request encryption key and nothing happens (it's been a week)... I can decrypt older and newer messages from the same user in the same "room" though.
If I can reproduce the bug consistently, I will file a bug report. It happens very often when you signin on a new device.
What you're describing sounds like a plain old encryption bug, although I'm very surprised you're still hitting it, given encryption in Matrix is pretty stable these days. If you can file a bug on github.com/vector-im/element-web/issues (or element-ios or element-android, depending on what platform you're using) with the full details or reproduction steps, I'll take a look.