The bug only occurs when doing a config change, which causes the LAN Ethernet ports to transition briefly into a non-forwarding state and back again. It only does this once per config change. This can be particularly nasty when people dual connect MX84's because it can cause short term spanning-tree loops.
It does not cause ongoing WAN packet loss.
You look like you have experienced a simple issue if the speed/duplex (probably the duplex) not being correctly auto-negotiated. If it only happens once I wouldn't do anything. If it happens again replace the cable.
This issue with packet loss when making config changes, will they ever fix that? We recently moved our phone system to an external datacentre and now whenever we make a config change the phones loose connection due to the packet loss and reboot. Which isn’t ideal!
The packet loss issue has been around for some time it seems, but will it ever be fixed?