Did you have multiple pages open in different tabs? If you get floating items in multiple tabs at the same time, it will usually only let you have one of the items and then make you wait before another one pops up.
I think it's because if you haven't clicked on one in a while then it registers that in the system, so you are eligible to receive floating items again. If you are working in multiple tabs then it can put up multiple floating items up at once because as long as you haven't clicked one yet then you would technically be eligible to receive them. But once you click on one then it registers that again and won't let you take the other one because it's been too soon. I hope that makes sense.
another reason for this is that you are not required to use the code that puts floating items in one corner of your page and puts an outline around them. The whole floating item during holidays thingy started for Vesnali and was an easter egg hunt. So if you are a user who is having fun searching at each page to see if there's a floating item, this method gives you all the time you need to find it. It also allows for you not finding it but still giving you the opportunity to get one when you are eligible on another page.