I did a dup from 20210810 to 20210828, and since then I noticed a very slow 
redraw on KDE Plasma: when scolling in a terminal or in a window, the screen 
looks 'broken' for a moment, then the rendering is back.

30: PCI 02.0: 0300 VGA compatible controller (VGA)
  [Created at pci.386]
  Unique ID: _Znp.WlxwpsiDkK3
  SysFS ID: /devices/pci0000:00/0000:00:02.0
  SysFS BusID: 0000:00:02.0
  Hardware Class: graphics card
  Model: "Intel CoffeeLake-H GT2 [UHD Graphics 630]"
  Vendor: pci 0x8086 "Intel Corporation"
  Device: pci 0x3e9b "CoffeeLake-H GT2 [UHD Graphics 630]"
  SubVendor: pci 0x17aa "Lenovo"
  SubDevice: pci 0x229f 
  Driver: "i915"
  Driver Modules: "i915"
  Memory Range: 0xe9000000-0xe9ffffff (rw,non-prefetchable)
  Memory Range: 0xc0000000-0xcfffffff (ro,non-prefetchable)
  I/O Ports: 0x4000-0x403f (rw)
  Memory Range: 0x000c0000-0x000dffff (rw,non-prefetchable,disabled)
  IRQ: 143 (1116926 events)
  Module Alias: "pci:v00008086d00003E9Bsv000017AAsd0000229Fbc03sc00i00"
  Driver Info #0:
    Driver Status: i915 is active
    Driver Activation Cmd: "modprobe i915"
  Config Status: cfg=new, avail=yes, need=no, active=unknown

Switching to nvidia chipset (prime-select) the issue is gone
Other users to confirm this issue (see factory mailing list)