Before I give away the answer I'll first state that the signaling logic is functioning as intended and there was been no photographic trickery. Still, Clear and Diverging Clear appearing next to eachother in this context should be contradictory. Here's I'm going to post another photo from a different part of the country that is a pretty big hint about what's going on here.
This was taken on the former ATSF Raton pass line where the last operational semaphores in North America are located. These semaphores are constantly being photographed, but nobody seems to be confused as to why adjacent signals can both display clear like this. Well, there are two reasons. The first is that there is something about Diverging Clear sitting next to a Clear at the end of a siding that just seems plain wrong. The other reason is because the sort of signaling where this circumstance occurs is much more common out west than it is in the east.
|This is your last hint before I give away the answer/|
|Surprise! It's a spring switch and its also not an interlocking.|
|Same situation, one less signal.|
Well, what's enough of me rambling on. Like I said this arrangement is far more common out west and there you don't see the Diverging aspect. This is why it is absolutely critical to have a good understanding of how traffic control applies to various methods of signaling. Realizing the line was running under Rule 271 with manual traffic control, it is clear how two trains could never take both routes simultaneously.