Freeciv

I'm using my personal ruleset for v3.2:
https://raw.githubusercontent.com/dftec-es/civ2civ3_earth/master/3.2/civ2civ3_earth-3.2.mpdl

The error log is:
in government_name_translation() [government.c::145]: assertion '((void *)0) != pgovern' failed.

I attach a savegame that crashes when I load it with QT client.
It might be related to the fact that I lost contact with the Romans, but there is an open diplomatic dialog with them, that I have not closed for some turns.

GTK loads the savegame, but the nations tab shows that Romans have government "null".
If I move the egyptian trireme (in the mediterranean sea) to a tile adjacent to the roman city, to gain contact with them again, and then I try to open a diplomatic dialog with the Romans, then the client crashes with the same error.