Huge jump in taxes after entering additional W2

I'll try to keep this straightforward.  I had entered 5 W2s for myself and wife (married, filing jointly) and TT showed refund due of $2300.  After I entered another employer (wife's), it changed to tax owed of $5100, a roughly $7400 jump from refund to owed.  There's nothing odd about the last W2 entered, and it did not bump us from one bracket to another, as far as my calculations tell me.  The only big difference is about $22000 of employer paid health care in the last W2.  Her withholding is a little lower than some of the others, but not by that much.  Any idea what could cause such a huge jump?