from past discussions, I've narrowed it down to 3 areas (where spouses I485 were approved later):
1. Marriage right before (ie. 6 months) filing an I485
2. Different filing dates
3. USCIS ranomness - notice that there often no rhyme or reason to their work. Previous posters have mentioned that even fingerprints were scheduled on different dates for spouses despite fiing the applications together.
So, your case may be normal (unless of course you were the dependant).
Anyone else have ideas?
rgds,
sadiq