The disconnectionScreen.unexpectedPacket exists in the binary and is seen in the wild from bad connections, the lang string is missing from the vanilla resource packs.
MCPE-159766
Missing language string for disconnectionScreen.unexpectedPacket
Resolved
Fixed
0
Related tickets, clearly this is causing confusion:
MCPE-156063
BDS-15545
MCPE-153181
MCPE-28724
It would be useful to get this translated, this will allow 3P servers and opensource software to make use of the string.