Turn Signal Problem-Resolved

Hey all, I have what seems to be an interesting turn signal problem on my 2018 TRD OR (And yes, I've topped up the blinker fluid!)
I'm having the problem where my left side signals will blink once, then stay out. If I turn it off for about 5 seconds, I can turn them on and they'll blink once again and then stay out. My right side works fine.
I didn't notice until I went to work on Monday, and I did wash my truck on Sunday. Could be coincidence, but may be worth noting.
Of course, in true TW fashion as well, nothing is stock. I'm running @MESO Total Tail stage 1, Mirror turns, and Stage 2 LED side markers, and then switchback DRL (Diode Dynamics if I remember correctly, BHLM by @no vtec 4me). Still conventional lamp in the headlight turn signal, but it's good (swapped left to right).
I haven't had a lot of time to trouble shoot yet, but have tested whether it changes with the rear, side markers, or DRL disconnected, with no change.
I appreciate any help!

 

I would check the bulb socket connections for corrosion and do a pin drag test make sure they are good as oem always fits better then aftermarket.

 

Took some more time to look at this today...
Went through and disconnected everything. Checked connections, no change. Disconnected all, then reconnected one at a time and tested, no change.
At this point, given that I get one flash before it stops working, I'm suspecting flasher. Research seems to indicate that it is no longer a separate unit on the 2016+, that it's integrated to the gauge cluster? Anyone with any experience on that?
Anyone with any other ideas?

 

After some further consideration, mostly around the thought that if the flasher was bad, I would think the problem would be bilateral, I went back in...
Turns out @Ronzio was on the right track...
Tracking the problem, I found that it went away when I unplugged the power to the side markers, not the molex to the LED, but the actual power lead. Tracing this back led to a sub harness that goes in line between the LED supply and the old turn signal connector. The problem was either that connection into the main harness, or that part of one of the wire splices there was ever so slightly showing copper out from the heat shrink. I reseated the connector and re-soldered and heat shrunk the wire, and the problem was gone.