Exactly as said in the title, the renshuu app stops playing any sound after a dozen or two clips have been played in a quiz. This started for me about 12 hours ago. Force closing and reopening the app makes sound work again for about a dozen clips, and restarting the phone doesn't prevent it from reoccurring.
This issue first happened earlier in the night, and that time it also corresponded with all widgets and app shortcuts but one on my homescreen being wiped out. Consequently, the sound issue is probably with my device itself, but since it only happens with renshuu, I'm wondering if that might give anyone here an idea about which system function may be messing up.
Android device/model: Samsung Galaxy S9+
Android OS version: 10
App version: 1.0.20210630
Edit: After letting the app idle for a bit before starting a quiz, I can confirm that it's time instead of or in addition to interval.