Originally Posted by
mattp1987
When I go
to Delta's lounge search, search for IST, and check the Sky Club member box it appears that the membership is not valid for admission to the SkyTeam lounge. However, searching for LHR as SkyClub member shows admission is allowed. As far as I know these are the only two SkyTeam lounges, so I don't know why the policy would vary between the two.

I agree : no reason to have different policies between the only 2 Skyteam lounges. Could it be that DL site has not been updated after the opening of the new lounge and so they still refer to the former 3rd party lounge ?