Something is broken with milestones.
I completed 16th quest > milestone poped up, and it gave 30 fragments for buccaneers bay upgrade kit
then it didn't disappered, but the button turned grey. > refreshed the game > still there, but can't collect again, just turning gray.
I completed the next quest (17th), now I could collect the trading post upgrade kit (but event window showed that it is buccaneers bay upgrade kit)
AND still didn't disappered, now it says "I completed 34 quests" and want go give me another milestone, but can't collect it, just turning gray, even if I completed the 18th quest.
In my other city, I completed 17th quest, gave me the milestone (correct), but didn't disappered, and now gave me the 30 fragments milestone, then the 34q milestone stucked on event window.