The title may be slightly misleading, since I’m not 100% sure if this bug affects only the Sylvari, but I noticed tonight when swimming underwater, that my Sylvari female was not wearing underwear. I’m providing screenshots of this, along with a screenshot of the armor I was wearing just in case it is tied to the armor.
I didn’t see this reported on the first couple of pages, so I don’t know if its been mentioned.
The last picture shows the armor in question. For all I know, though, it might happen with all armors.