Candidate's unable to set email and phone number both the options as preferred communication methods

An external candidate should be able to set his/her communication method to both email and phone number once they have applied to a Req.

In our case, we are not able to select both methods at the same time even after applying within a Req.

As can be been seen below - the use for communication box is grayed out. (This screenshot has been taken after applying to a job req as an external canddiate and then editing the personal Information)

Anyone else faced this issue?