Go to your linked accounts in your profile, select the account that has duplicate transactions, and tap "Refresh."
If that fails to remove the duplicates, try deleting and re-adding your institution. You can delete your institution by selecting the account and clicking "Delete account" on the bottom. Then, re-add the account and check again for duplicates.
If neither of these resolves your issue, please reach out to Albert by clicking "Contact support" from the profile screen.