As of the last week or so, the Rich Content Editor is stripping border-radius from inline styles whenever a page is saved. Pages built earlier still have it (so it's not the stored content), but the moment a page is saved through the editor, every border-radius is removed from the HTML.
This looks like a regression, because border-radius is still on the official HTML Editor allowlist (updated Jun 1, 2026) and in the public canvas_sanitize source.
Minimal repro — paste via the </> HTML editor, Save, reopen the HTML editor:
<div style="padding:10px; background:#e1edf0; border-radius:12px;">rounded?</div>
On save, border-radius:12px is gone; padding and background survive. Same result for single values, percentages, multi-value, and the corner longhands. border, flex, and gap are not affected — only the border-radius family.
Can others confirm? Trying to work out whether it's the editor (client side) or a server change.
Two concerns: (1) a lot of existing course design relies on border-radius and is now visually broken, and (2) more importantly, if a documented-allowed property can disappear on save, it undermines confidence in using inline CSS at all — we need the allowlist to be reliable to design against it.
