I can see a confirmation downlink was sent, but did your node receive that?
For frame counter 16, the next uplink with the very same frame counter is 6 seconds later. I doubt such delay could be caused by a slow gateway (if the packet was even received by multiple gateways), but maybe some other problems (like slow handling of some queues in the backend servers) could cause the same thing.
For frame counter 15 the difference is only 1 second, so maybe that’s a slow gateway after all.
So, to tell if both uplinks are received by the same gateway(s): peek into the uplinks’ metadata by clicking on both the 15:54:20 and 15:54:26 lines. (And while looking there: also compare the channels/frequencies that should be different for a retry.)
Yes, and: no. If the node did not receive the confirmation then it would have retransmitted the uplink, and hence have requested a new confirmation. The “retry confirmed” is displayed on an uplink, so that’s a message as sent by your node, not by TTN. (And yes, after that, TTN has sent another confirmation downlink.)
Why not?
As an aside: the seconds in the timestamps are weird; it looks like TTN sends downlinks before it even receives the uplink that requested it (like the downlink at 16:54:19 for the uplink of 16:54:20).
And on a related note: it seems you’re sending all your uplinks as confirmed uplinks. Your node can use at most 10 confirmed uplinks per day.