Strange Left Turn Signals in Irving

I found these strange protected permissive left turn signals in Irving near my hotel. They can run protected lefts in both directions or split phase with the straight through green. The left turn signals could achieve the same goal by being protected only since there’s never a permissive only movement at this turn.

[@WestCoastTrafficSignals]

The “left turn yield on green” sign makes no sense! Odd displays as well, but probably an old standard as you mentioned. Looks unchanged from the earliest street view imagery I could find (2008), except they added that left arrow for the side-street.

[@JMANWiSS]

Really scratching my head as to why an intersection with what looks like actuated signals is running a fixed timing and serving empty movements.

[@TheTrafficTech]

@@JMANWiSS yeah I noticed that too. Could have been running max time during certain day plans!