I'm not suprised. Telling one government agency you're married (USCIS), and the other one you're single (IRS) can raise eyebrows and question geniunity of marriage. At least that's what my immigration lawyer told me.
Especially if conversation was mostly about tax return, means officer wasn't super happy about this arrangement. I guess, out of 100 officers, 95 wouldn't pay attention to it and 5 would be obsessed with it.
On the other hand, if I-130 is approved, this means marriage is bonafide in the eyes of USCIS.
I-485 is all about different inadmissabilities related to immigrant's prior trips to the US, their interactions with law, security background, vaccinations etc.
Keep us updated @Khas061682. Hopefully it's just a small hold up.