Any problem with entering on a B2 after being married abroad, then filing for change in status? Spouse is US citizen.
Yes, there is a problem with doing this. If you intend to immigrate to the US then you do not qualify to enter as a visitor as defined at 8 USC 1101(a)(15)(B). The "B" here is the B that gives the B-2 visa its name, so this means that an intending immigrant is not eligible to use a B visa to enter the US.
The ability to "adjust status" from B-2 to that of a lawful permanent resident is therefore by implication available to those whose plans have changed after admission to the US.
There is a K-class "spouse visa" for those who want to enter the US and then apply for adjustment of status, but it is apparently not very useful lately, because the K visa process takes as long as the "normal" immigrant visa route with consular processing.
If you apply to adjust status after entering in B-visa status, you might run up against a presumption of misrepresentation, in which case you would be permanently inadmissible to the US under 8 USC 1182(a)(6)(C) unless you can overcome the presumption. To do that, you would have to show evidence that you did not intend to adjust status when you entered.
You should certainly not do this without first consulting with a reputable US immigration lawyer.