MDX currentmember inconsistent?

MDX currentmember inconsistent?

Is there something that I am missing here or is this just not working:
This query is working as expected:
select non empty [Measures].[Reseller Sales Amount] on 0,
Filter (NonEmpty({[Geography].[Country].[Country].ALLMEMBERS *
[Geography].[City].[City].ALLMEMBERS}), [Geography].[City].Currentmember
IS [Geography].[City].&[Seattle]&[WA]) on 1
from [Adventure Works]
This one works too (different result, as expected)
select non empty [Measures].[Reseller Sales Amount] on 0,
Filter (NonEmpty({[Geography].[Country].[Country].ALLMEMBERS}),
[Geography].[City].Currentmember.MEMBER_CAPTION = 'Seattle') on 1
from [Adventure Works]
This one though, which should produce the same result as the previous
query, does not work:
select non empty [Measures].[Reseller Sales Amount] on 0,
Filter (NonEmpty({[Geography].[Country].[Country].ALLMEMBERS }),
[Geography].[City].Currentmember IS [Geography].[City].&[Seattle]&[WA]) on
1
from [Adventure Works]
Am I missing something?
Thanks.