I look site manager (location manager) this morning and 20 buildings lost all aps, and there are no one in Unspecified location windows. WLSE is 2.15.1.
I have use a backup copy, but the error dont resolved. And all aps are in device center.
All lost aps are 1131 and 1241 with ios 12.4.(10b)JA. All 1100 aps are in location manager.
I update ACS (3.3.3 to 4.1) this morning, if this can help.