I was making a farm so I put a sign next to the on/off switch with the exact message:
"§l§fOn§0/§4Off"
I then put glow ink on it and the letter "n" and the "/" were z-fighting near the bottom.
[media]
MCPE-160590
Z-Fighting in Sign Text
Open
6
(Unassigned)
884900
Confirmed
Multiple
Windows 11
1.19.20, 1.20.51 Hotfix, 1.21.0
Retrieved
I can confirm there is indeed z-fighting happening with this text and glow ink