Navigator is not expected to transmit on UHF, so probably it is one of the other satellites, maybe one of the LEMUR sats.
I’m going to add it as Unknown 3 T17 in DB and use the TLE we used for Navigator and try to track it:
Unknown 3 T17
1 98255U 26194.91264639 +.00001273 +00000+0 +12977-3 0 00151
2 98255 97.7562 95.2673 0010603 128.0611 232.1566 14.92374984000981