If you copy & paste an element that has an interaction from within a symbol, that copied interaction only works on that page you’re on regardless if that symbol is found on many other pages. A workaround is to remake the interaction on the copied element; then it will work on other pages that have the symbol. This could be frustrating for many to figure out.
It’s tough to say if this is a bug or not without a Read-Only link to check into — can you please share one to a project where you saw the issue?
That said, if you are using an interaction that’s affecting elements across multiple pages, you’ll need to make sure you’re using class-based animations and not targeting only elements.