This is something we’ve seen before - there are two separate issues at play here. The doubled output (where each math symbol appears twice) is caused by the MathML annotation not being properly hidden by CSS, so both the rendered math and the raw annotation text show up. The red-text collapse happens when the model outputs nested math delimiters (like \( inside a \[...\] block), which triggers a KaTeX parse error that cascades across the rest of the response.
Your console workaround hiding .katex-html is smart - it works because your browser natively renders the MathML, so hiding the KaTeX HTML output leaves only the clean MathML rendering. That said, it’s a temporary fix that resets on reload.
Our team is aware of several math rendering gaps in the chat interface and is actively working on improvements. I don’t have a specific timeline for when this particular combination will be resolved, but I’ve flagged it internally.
In the meantime, the console snippet you found is the best workaround available. If you want math content to render more reliably in general, you can also add a User Rule like:
When writing mathematical formulas, use $$...$$ for block math only. Avoid nesting math delimiters. Never use \( inside a \[ block.
This can reduce how often the model triggers the parse error cascade.
