It seems like an oversight that the Waking Sands and similar locations (from memory: the Rising Stones, Camp Dragonhead intercessory, Fortemps Manor and Ruby Bazaar office) are not counted as sanctuaries. Rested bonus doesn't apply, and glamour plates can't be used.

Lore-wise, I think the 'sanctuary effect' is supposed to come from aetherytes, in which case it does make sense that the Waking Sands itself is unaffected, but all the other locations are within in aetheryte zones.

Has this been asked about or explained before? Is it something technical to do with them being variable instances, perhaps?

It's not a big deal, but it's a little annoying, and I'm curious.