I can’t help but wonder if these issues are part of a bigger problem related to 広域マップボタンや方位磁針ボタンなど、画面の上部がタップできなくなる / Buttons at the top of the screen are sometimes unresponsive. I’m still getting the problem of not being able to tap the gyro button on the first launch of the game for the day, pretty consistently, and it’s the time where there are many notifications coming through, especially if I log in after 9am local time and the game displays several notifications in the game, such as the safety warning, the replenishment of supply items in the shop, the friend quest progress, news and announcements, and sometimes even the Driftsmelt completion too. After going through all those notifications and then starting a hunt, I would almost always find myself unable to tap the gyro button during the hunt.
However, I personally have never encountered the issue with not being able to tap the Driftstones in the Driftsmelt screen.