I'm not sure if I've lost some rubber/plastic bushing or if something else is going on.

If the latch is moved slightly forward, it will pop loose on its own, without releasing the locking tab.

Action here:
https://youtu.be/MKP1dKFxbPA

Is this a known issue that can be fixed? The actual latch mechanism looks like it's riveted together. I'm not sure how to stop worrying about my hood popping up on the freeway short of getting hood pins.

If it were popping loose without touching the handle then I'd say you have a problem. But your latch looks like it is operating like many I have seen, in that it opens to the 1/2 way point. I believe it's a built in safety feature that still retains the hood from flying open while traveling down the highway. Try to pop your latch 1/2 way with the hood in the closed position and then try to lift the hood. Or else try closing the hood just til it latches 1/2 way and they try to lift it without touching the latch. If it does open then I'd replace the latch mechanism. I've closed the hood 1/2 way once or twice on my 01 Ram, thinking I'd open it again and forgot it, and drove off without it flying open.

Well, I know I have a problem because it keeps popping open on the highway every now and then despite being tuggy-tight sitting still. 55mph+ air blowing at the hood + bumps seems to let it wiggle free easily. I probably just need a new latch.

my guess is the spring that holds the pawl in the latch that secures the latch lever is broken or the pawl is rusted up or worn out.

your options
try lubing with penetratant and hope it free up.
disassemble and repair latch
most likely you probably need a new latch

I used to have the exact same problem with my 67 Coronet. Before I did anything I adjusted the hood latch assembly so that I had to shut my hood a little harder (a soft slam) to close it and that did the trick. It's been about 4 years since I've had it happen.

I used to be able to shut my hood without slamming it. I would just close it and then press it down with my hands and it would latch. But if I hit a bump at highway speeds it would pop open to the secondary latch. Only happened twice but it was very scary when it happened.

That's exactly how I have mine set up, just push to shut - I'll try lowering my latch to a "soft slam" point and see how it works for me on the loop highway in town. Thanks for the tip!!

No problem, and good luck