Thank you elrond for reporting this to us. This seems similar to something I recently reported (FOE-26763) and it might be caused by the same issue but the details are not a perfect match.
As you do not see the remaining boosted collections in the app itself, once you've used the boosted productions you simply receive less resources (coin, or supplies in your case) BUT the tooltip information above the building wrongly displays that you'll get boosted collections. So the tooltip might say 8k supplies but upon collecting you get 3k supplies.
To make sure this is a different case, when you see the collection numbers on your iphone, please don't collect them but open the game through the browser and check how many boosted collections you have remaining, if any. Then collect from the iphone. Let us know what you find out and we'll pass along that information - thanks!