Thank you for the video and for helping us verify the behavior, @GRAPHICPROF.
I was able to reproduce this, and I can confirm that it is not expected behavior. After relocating the ruler origin, View > Guides > New Guide should calculate the entered position relative to the relocated zero point.
In the affected behavior, the rulers correctly recognize the new origin and manually dragged guides also use it correctly, but the New Guide dialog continues to calculate the guide position from the document’s original (0,0) point.
We already have this issue tracked with the Photoshop team, and I’ve added the details from your report to the existing investigation.
Workaround:
In the meantime, I found a workaround that restores the expected behavior:
1. Go to Photoshop > Settings > Technology Previews on macOS, or Edit > Preferences > Technology Previews on Windows.
2. Turn off Modern User Interface.
3. Move the ruler origin again and use View > Guides > New Guide.
With Modern User Interface disabled, the New Guide dialog should once again respect the relocated ruler origin.
The downside is that disabling Modern User Interface switches affected Photoshop dialogs/UI back to the previous interface, so that you may notice differences in the appearance or behavior of other updated dialogs. You can turn it back on at any time; this is only a temporary workaround while the underlying New Guide issue is being investigated.
Thanks again for the clear report and recording.
Best,
Anshul Saini