Both front turn signals are having issues?

Hello all, first time prius owner here. 2013 Prius Plug-in, 137k miles.

When we bought it, we neglected to check the turn signals in the front and noticed a weird issue only after we got home. The rear signals worked great, but neither of the front ones would light up. And the signal itself made an irregular rhythm inside the cab.

I replaced the two front bulbs, and still had the same issue.

I replaced the flasher relay, the one located inside the car about a 18" above the brake pedal. And that fixed the irregular flash rhythm. But I still had no front signals.

But inspecting it in the dark, I realize that both front turn signals actually flash, just very dimly (using either turn direction). Pressing the hazard button makes the rear ones flash just fine, but the front ones don't flash at all.

If I remove either of the front bulbs, neither of them will flash dimly by themselves. I removed the front fender and located the grounding wire/bolt just below the main headlight on the drivers side. I checked for continuity from the turn signal plug ground to the bolt ground, and it was good. I also checked the positive of the plug to the bolt ground, and it also had continuity??? I realized later I forgot to check continuity from the grounding bolt to another piece of metal (like the engine).

The peak voltage I measure inside the turn signal plug varies between 8-14v.

I also turned on the daytime running lights DRL, and realized that BOTH FLASH at full brightness whenever I activate the right or left turn signal. I'm not sure, but I don't think that's supposed to happen either.

Any help would be appreciated. I have a basic understanding of electronics and I've worked on plenty of personal vehicles, but I'm a little stymied with this one.