Pixel Perfect Camera - Edges of sprites (only) aren't correctly sized

Presumably just some setting I'm forgetting about? But I noticed that all my sprites will look weird along their edges. I'm stretching pixels to be 3x larger. I took this screenshot of the game running full screen, added some white there in post just to highlight the odd sizing. The anomalies around the sprite's edges follows only that sprite everywhere. It's not a "squish/stretch phenomena" that's stationary to that screen coordinate or how to put it. If any other sprites are behind or in front of it then you can more easily notice how they either bleed over or don't reach a full pixel against each other.

This only happens at the very edges of the actual sprites' files. If I extend the image canvases to give them a single pixel of transparency all around it isn't noticeable. Presumably the anomaly still happens, it's just transparent pixels affected.

I'd rather not reply on such an annoying workaround though. I don't even fully trust it to be foolproof in every scenario. Any advice what I might have gotten wrong?

I've got 32 PPU on sprites and camera. 640 360 resolution.