"The game engine has encountered a logic error. The %s #%u of player %u could not find a way from (%i, %i) (with %s immovable) to the opponent (%s #%u of player %u) at (%i, %i) (with %s immovable). The %s will now desert (but will not be executed). Strange things may happen. No solution for this problem has been implemented yet. (bug #1951113) (The game has been paused.)"
https://translations.launchpad.net/widelands/trunk/+pots/widelands/nb/443/+translate
This clearly refers to bug 1951113, which doesn't seem to be on Launchpad (they haven't passed one million reports yet). Checking the line in question, this doesn't seem to have been changed since r4677 (when it was committed by Sigra). I am a bit confused why this showed up in translations now, as I can't remember seeing it before. Anyways I suspect this might refer to an older bug number from the sourceforge tracker, and if this issue hasn't been fixed yet, it should be updated to point to the corresponding Launchpad bug report.
According to https:/
This bug is set Won't Fix. But I can't see why.