On ThinkPad P1 Gen 3, I installed NVIDIA-Linux-x86_64-470.63.01.run, when I switch to external only, I could reproduce this issue.
It used Intel for redener, and nvidia for output by default.
$ glxgears -info
Running synchronized to the vertical refresh. The framerate should be
approximately the same as the monitor refresh rate.
GL_RENDERER = Mesa Intel(R) UHD Graphics P630 (CML GT2)
GL_VERSION = 4.6 (Compatibility Profile) Mesa 21.0.3
GL_VENDOR = Intel
On ThinkPad P1 Gen 3, I installed NVIDIA- Linux-x86_ 64-470. 63.01.run, when I switch to external only, I could reproduce this issue.
It used Intel for redener, and nvidia for output by default.
$ glxgears -info
Running synchronized to the vertical refresh. The framerate should be
approximately the same as the monitor refresh rate.
GL_RENDERER = Mesa Intel(R) UHD Graphics P630 (CML GT2)
GL_VERSION = 4.6 (Compatibility Profile) Mesa 21.0.3
GL_VENDOR = Intel