Please clarify about the actual component values and how you measured phase shift. An all-pass build with a 7 MHz OP can't give ideal behavior at 2 MHz, but should at least show some phase shift. More likely you have still unsuitable component values or some other circuit fault.
Please consider that the chosen OP can output 2 MHz signals only with small magnitude (e.g. below 100 mV) due to limited slew rate.
For good performance, the OP GBW should be factor 10 to 20 larger than operation frequency.