There are a few times when the interface drops and gets up gain, not sure from the log why.
This is probably your Ethernet card: e1000e that the log refers to as going down and up.
This might be a interesting thread. I’m not certain it applies to this situation but the op in the thread has similar symptoms and from the log the same network card.
Could you posts some more info about your system and maybe the error log from the journal?
$ inxi --admin --verbosity=7 --filter --width
$ journalctl --boot --priority=err