gradient contrast issue when switching theme

[GUARINOO]

Captchas

• I have read the instructions.
• I have searched existing issues and avoided creating duplicates.
• I am not filing an enhancement request.
• I have checked that this issue cannot be reproduced on Mozilla Firefox.
• I have checked that this issue can be reproduced once I removed all my Mods and Custom CSS.

What happened?

Have not had this issue before 1.12.8b

Steps to repro
set a theme color
set your desktop mode to light mode
while zen is open, switch to dark mode then back to light

What happens
text remains black when contrast should be updated to white
transparency is mostly not working
colors are darker than in light mode previously

What i expect to happen
zen sidebar theme returns to inital color from when light mode was set

browser refresh fixes the issue

Version

1.12.8b

What platform are you seeing the problem on?

Windows - x64

What component is this issue related to?

Customizable UI / Toolbars

Relevant log output if applicable