Amadeus Cow Cup Spout Covers won't stay on!

[Essie3]

Random one.
I have one of these Amadeus Cow Cups and they're cute.
But they have these spout covers (I got 2 with mine), but they won't stay on the spout! They did in the shop, and before I used the cup, but now they're all loose and I can't take the cup in my bag because it leaks everywhere.

Have I got a faulty one or something? Or is this how they are?

I've never used the cover as they did not stay on mine either.

If I ever used it out and about I just put the drink in a water bottle then poured the drink into the Cow Cup when needed.

That's how they are, the covers are pointless!

Yup same problem here... I think they warped in the dishwasher?

Not just me then!
I don't quite understand how they were so stuck on in the shop, but then the minute the cover has been removed the once, you have a pointless bit of plastic which basically rests on the spout, serving no purpose! Maybe they use invisible glue or something which washes off.

geordieminx mine weren't dishwashed - just took them off, washed the cup, and then suddenly it didn't work.

Thanks all!