Some browser extensions — particularly dark mode tools — modify page HTML in ways that affect Bubble's "Built on Bubble" banner. Because apps on the free plan are required to display this banner unaltered, Bubble detects when it has been changed and shows a reminder warning.
What you might notice
You see a message warning that the Bubble banner has been removed or altered
This happens even though you didn't intentionally hide the banner — a browser extension changed it
Workaround
Check your browser extension's settings for a per-site or per-element exclusion option, and exclude your Bubble app's domain. Alternatively, disable the extension while viewing your app. Note that intentionally removing or altering the banner on a free plan app is against Bubble's terms of use.