Also I got two warriors when start new save, invite warrior, but browser bugged and keyboard isn't working, I refreshed page, and accept warrior, but got two in party...
I wasn't look at source how you implement saving, but for my own projects I use indexed db and two saves with cycle between them like some device bootloaders do for formwares. (It's can help if save just corrupted or lost by no free space to write on user device when saving)
Also I some times see message about another tab locked save, with only one tab with the game.
