Is this supposed to happen? Subeta got crammed so much in the modal that the error text isn't even readable.

This happens when you try to click a floating item (in this case, likely a flower) after you've opened a new tab, or navigated backward a page, and the new page has a flower on it. You collect the new flower, and then the old one is no longer valid.

The error does load the entire page just within the little error window, it has always done that, but that's what the error is telling you.