The outside triangles are not generally glued to the suit, they are pegged to a disc inside the suit which is glued on the inside most times.
Mine did the same as agons, one broke one popped out of the disc. I think there was a possibility that HT considered making the cape removable, since it was clearly not as permanently attached as it could have been, but still it's not something you do lightly.
Personally i'm all for replacing the cape but its only if your intending to keep this figure and don't care about resale value or any of that stuff, because to make it correct you will need to put the clasps onto the cowl, you could (assuming you get them out with their pegs) presumably just put them back with a new cape but they would still look incorrect and part of the replacing the cape is to correct the placement of the cape clasps.