My guess:
In a channel scan, either your ATSC decoder (if your TV is digital ready, it's still there, only it's inside the set itself), or your signal from KPRC, was imperfect.
Your receiver caught the presence of a signal on RF channel 35, and caught the fact that the virtual channel is 2, but somehow missed the data telling the receiver that the programs were .1 and .2
When your receiver detected the streams 35.3. and 35.4*, it rendered then as 2.3 and 2.4 rather than 2.1 and 2.2
*little-known fact: When they introduced PSIP to the ATSC standard, they marked streams n.1 and n.2 as unusable. Almost anytime you are watching the main program on any given channel (virtual ch).1, that stream is really (actual ch).3, not (actual ch).1