My alliance seniority was reset to from 931 to 0 without me leaving the alliance: http://www.cybernations.net/nation_drill_display.asp?Nation_ID=437926
The only edits I have made to my nation today are changing my Defcon, Threat Level, and Religion. I believe my religion was changed at around the timestamp of the Seniority reset, though I wasn't paying attention enough to say for sure.