Tithe barns are bugged. The source of the issue is the upgrade > attributes> races> mongol> research> unit > upgrade_unit_religious_tithe_barn_4_improved_mon
under action trees, the action tree opening branch calls common_upgrade_completion_events_\speech_celebrate\celebrate.
It should be calling a variation of the upgrade_religious\upgrade_unit_religious_tithe_barn_4_improved_mon
Source: Am modder and I do qa work 