Intermittent CSS styling breaks in preview environment

CSS styles randomly fail to load in the Lovable preview iframe. Custom theme colors revert to browser defaults (white backgrounds, invisible text). The issue is intermittent - sometimes fixes itself after a few seconds or navigation.
Details:
Tailwind CSS variables (defined in index.css) occasionally don’t apply
Text becomes invisible, backgrounds show default white instead of custom dark theme
Production build works perfectly - issue is isolated to the Lovable preview environment
No code changes were made when the issue started appearing
Console shows: cdn.tailwindcss.com should not be used in production (Lovable-injected)
Workarounds tried:
Hard refresh (sometimes helps)
Navigating between routes (sometimes helps)
Opening preview in new tab (sometimes helps)
Expected: Preview should consistently reflect the same styling as production.
Environment: React + Vite + Tailwind CSS + CSS custom properties for theming

Seems like an internal issue with Lovable, they are aware of it. The hard refresh is a good option