Note: Devices that only send and receive faxes are not affected by this issue. Only multi-purpose (or combination) fax/telephone devices that use an auto-recognition mode to identify incoming calls are affected.
As a workaround, ask the recipient to set the device to receive a fax manually, then send the fax. Or, ask the recipient to set the device's receiving mode from auto-recognition to "fax only". Instructions should be available in documentation that came with the device.
Note: Even when the device is in "fax only" mode, you should still be able to use it for voice by picking up the receiver while the device is ringing.