I saw that the "archer" achievement was locked, which really caught my attention since (kill a creeper wit arrows) is something I did many times in the game, however the achievement was not unlocked,
I tried to kill the creeper with skeleton arrows and it only gave me discs but not my achievement, I used the crossbow and still I still do not achieve the achievement,
I asked to borrow the pc from a colleague who had bought minecraft for Windows 10, since I only have the version for Android, to verify if the error was exclusive to my device but after killing several creepers only with arrows the achievement continued locked and instead of "archer" the achievement I acquired was "camouflage" and then I understood that this was a bug
Thank you for your report!
We're actually already tracking this issue at MCPE-86371, so I will resolve and link this ticket as a duplicate.
If you would like to add a vote and any extra information to the main ticket it would be appreciated.
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