P: Images opening unexpectedly small (macOS)

They should also do something with your other problem reffered to 2 monitors:
https://feedback.photoshop.com/photoshop_family/topics/photoshop-zoom-moves-image-window-to-wrong-sc...

This is still happening to me as well with 2 monitors.

And then something similar happens when I move the image to the 2nd monitor and zoom into the image using "Resize Windows to Fit" or Command + 0 (Fit on Screen). The image is automatically moved to the first monitor (zoom is applied and squeezed in the space available next to the windows/palettes).

It's interesting that you're seeing this with three monitors. We tested it with two, so I will be curious to hear if the next update resolves it for you. Someone will post to this thread when that update is available.

Thank you,
Hannah

This is still happening for me, Photoshop version 19.1.3. I'm using Windows 10, not OSX, but I guess from reading the above it doesn't matter.
I'm opening images by dragging them onto the Photoshop window, and I am using 3 monitors. This never happened before this update.

I should mention that I'm running OS 10.12.6. So it seems that 19.1.3 fixed the issue with some and created the issue with others. 

With the 19.1.3 update on MacOS 10.13.4 and two monitors, I don't have this issue anymore. However, if I have my workspace in full screen mode and open a second image, it opens smaller and has a black border on the right and bottom of the image.  I can fix it pretty easily by switching between open documents, but I was  just mentioning it.

Not really. Didn't fix the issue.

Simple solution for this is go to window - workspace - reset ..all you done.

I never had this problem before. Unfortunately, I just installed 19.1.3 on the Mac and this issue suddenly appeared. I do have dual monitors. It's a really annoying bug. I did implement the action fix, but would prefer that the bug be fixed.

*The only workaround, besides Jeffery Tranberry's workaround. That one worked for me - even from opening from file folders in finder windows. I was offering James another solution if the other workaround doesn't work for him.