I don’t see anything wrong in this log. Probably the issue is related to the state of your network, not ssh.
Maybe the rooter?
Although not completely sure about it, it seems that the problem is really more likely related to some incompatibility between new NM release and the usb network connectors I have here. Now, with a new usb network connector, ssh’ed sessions are much better …
The old usb connector uses a kernel module r8188eu and the new one uses ath9k_htc.