On a MBPR 13 (early 2015), the AmazonBasics Thunderbolt to VGA adapter doesn't work with the monitor's native resolution??

I've got the latest MBPR 13" (early 2015) and am trying to use the AmazonBasics Thunderbolt to VGA adapter with my external monitor. However, when I plug it in, the resolution on the monitor is apparently 800x600, or I can scale it to 1280x1024, which looks super awful and washed out and of course stretched out.

But if I plug in an authentic Apple adapter, it works without issue and looks great.

The reviews for this adapter on Amazon are excellent--has anyone experienced this issue? I've tried multiple AmazonBasics adapters on multiple monitors but it refuses to work.

Help! And hopefully the solution isn't "go buy an authentic Apple adapter and stop using the Amazon one" because that should not be the case.

Thanks!