Happened again after 14 minutes of gameplay. I have it on video.
I ran scr_kill_infinite_loops 1;developer 1 at the beginning of the game.
This is the bottom of console_zm_log:
DB_LoadGump async zm_transit_gump_town
DB_LoadGump gump file zm_transit_gump_forest2 is loaded
DB_FlushGump 0
Unloading fastfile zm_transit_gump_forest2
Sys_GumpFlushed set gumpFlushedEvent
DB_LoadGump calling DB_LoadXAssets
Loading fastfile zm_transit_gump_town
DB_LoadGump end
send gump_flushed notify to script
Built adjacency info for IPaks 23ms
Sys_GumpLoaded set gumpLoadedEvent
send gump_flushed notify to script
Writing stats...
GScr_loadGump zm_transit_gump_busstation 0
DB_L