This is what i found, we had lots of packet loss on this remote peer IP address was causing isakmp to not correctly form SA (it could be any variable) but when i create new VPN gateway on cloud and with same configuration it works and we have no packetloss on that new gateway.
ASA# show crypto isakmp sa
Session-id:21, Status:UP-ACTIVE, ...
I'm taking a bit of a guess here.
ASA-4-713903: is a VPN peer misbehaving. With a follow on description.
In your case you are seeing discards due to packet size, related to the peer. I believe this is an Ikev2 Keepalive mis-match.
It appears that your end of the tunnel does not match their end of the tunnel for keepalive packets. Keepalives would be ...
It's giving you that/those error(s) because removing that object would leave the access-list empty but still existing, which is not possible or allowed, and you can't delete an access-list like that (by just saying "no" on its only line).
What you need to do is:
clear config access-list out2in
This will disassociate the access-list with the interface and ...