[Self-hosted] Theme color isn't applied or overwritten

Observed behaviour

After finishing the instance setup with the selected color in this case: #7b2ce4 (a purple), it then shows up applied to what appears to be --brand-primary for a second before being overwritten by the blue color fluxer uses, and any further attempts to change it in instance config is ignored. *sidenote the branding appear correctly on the progressive web app

Reproduction steps

Set a custom theme color during setup or in the instance config
Then nothing changes

Build information

Stable Web 2026.904.231615, Linux (x64), Firefox 154.0, Locale en-US

Platform

Self-hosting

Evidence

image