I believe this is due to the fact that files that you just archived doesnāt get unloaded right away (which removes them from the tag pane). Thereās a timer that verifies itās synced and sometimes later unloads it.
Global search on the other hand deliberately skips any documents that is archived, so even if itās still not yet unloaded, it will skip searching that document.
Iāll file a ticket to have archived documents removed from global tags immediately, but it isnāt too big of an issue right now.