Thanks,
So, even with connected phases they will have 1.4us phase difference?
That definitely was not the expected behavior:
https://e2e.ti.com/support/applications/motor_drivers/f/38/t/144259 specifically suggests to tie outputs together.
http://www.ti.com/lit/an/slva320/slva320.pdf specifies similar approach with multiple devices.
If following the above line of thought will fry the circuit I suggest you add a warning in the datasheet.
All the best,
//Rune