My default scaling of my laptop display is 175% at 2520*1680 with 60 hz.
When I connect an external display, this resets to 100% scaling for both displays, as far as good, no real problem here.
When i disconnect the external display, it doesn’t go back to the 175% but stays at 100% scaling.
OS: Manjaro 25.0.7 Zetar
Kernel: x86_64 Linux 6.12.41-1-MANJARO
Uptime: 5h 8m
Packages: 1559
Shell: bash 5.3.3
Resolution: No X Server
DE: Xfce4
WM: Xfwm4
WM Theme: Matcha-sea
GTK Theme: Matcha-dark-azul [GTK2]
Icon Theme: elementary
Font: Noto Sans 10
Disk: 409G / 917G (47%)
CPU: AMD Ryzen 5 5600H with Radeon Graphics @ 12x 4.28GHz
GPU: AMD Radeon Graphics (radeonsi, renoir, ACO, DRM 3.61, 6.12.41-1-MANJARO)
RAM: 12491MiB / 15338MiB
Mod edit:- All code or command output should be placed withing preformatted text boxes. This has been corrected for you this one time. In future, you are expected to do this yourself. See How to Post Command Output as Preformatted Text 
Please provide system information as described (below) and also note the Moderation comment in your first post.
The links given (also below) will help you use the forum more effectively. It is expected that you follow them and use the practical information found to help attract quality responses.
With regard your issue, the following link might give some background as to why some of these issues with m,ultiple monitors on HDMI can occur;
If your issue doesn’t strictly fall under that scenario, I’m sure someone can help further when they are able.
Regards.
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