I have a strange issue which is 100% reproduceable. When down-sizing an image, a transparent edge is introduced by Ps on the edge of the image. It's not just a display bug.
Here is how to reproduce. The specific image sizes, colors, etc. are not significant - just using those because I know it recreates the effect.
Create a new document in Photoshop with a size of 414 width, 132 height, 144 pixels/inch resolution (RGB Color, 8-bit)
Fill with a color, in this example #2b0849
Click the padlock on the background layer to convert it to a normal layer. The sole layer is now called "Layer 0" (Ps has renamed it)
Resize the canvas to 414 x 414 so the image is square
Create a new layer ("Layer 1") and move it underneath Layer 0.
Now fill that layer ("Layer 1")with the same color (#2b0849). The entire image should now look like it is one solid color.
Finally, resize the image to 300 x 300. I'm using constrained proportions and automatic resample but I've played with other resampling options (not exhaustively) and it doesn't change the outcome.
You will now see a thin layer of unfilled color around the edge of Layer 1, as if the layer was not completely filled. Layer 0 is fully filled, but Layer 1 is not.
I'm wondering if this is my own ignorange of Photoshop or a bug. I'm using 22.2.0 on macOS. This scenario was artificially created to demonstrate the bug but closely matches an actual workflow where I'm taking a rectangular image and centering it in a new square document.
Here is the image before resizing (after step 6, before step 7):
And here is the same image after performing step 7 (resizing):