Description:
After upgrading to noto-fonts 20201206-1, characters move around under mouse pointer in Firefox's and Thunderbird's interfaces. The font is set as default in Plasma.
After downgrading to noto-fonts-20190926-4, the problem disappears.
In chromium and other gtk3 apps problem seems to not exist. Inside Firefox, the site contents seem to be unaffected, but the font seems fuzzier than previous version (maybe just autosuggestion).

Additional info:
- noto-fonts-20190926-4
- freetype2-2.10.4-1
- plasma-desktop-5.20.4-2
- plasma-framework-5.77.0-1
- qt5-base-5.15.2-1
- gtk3-1:3.24.24-1
- firefox-83.0-2
- mesa-20.3.0-3
- Intel Open Source Technology Center -- Mesa DRI Intel(R) HD Graphics 4000 (IVB GT2)
- Kernel driver in use: i915


Steps to reproduce:
1. Set noto-fonts (eg. „Noto Sans 10”) up as UI default
2. Start Firefox or Thunderbird
3. Move the pointer over the tab bar and move the cursor around above it
4. See the characters dance

Attached:
- Bug video example
- Plasma font config
- `ls -l /etc/fonts/conf.d/`