When the iPad goes into sleep mode, normally after a minute or so of no input into the game, on the automatic restart there is no sound in the game. This does not seem to be able to be rectified from the control centre or from saving and quitting and reloading the game. The app needs to be manually closed or the iPad restarted and the game reloaded for the sound to be restored.
Related issues
Comments

Thank you for your report!
We're tracking this issue in MCPE-144270, so this ticket is being resolved and linked as a duplicate.
If you would like to add a vote and any extra information to the main ticket it would be appreciated.
If you haven't already, you might like to make use of the search feature to see if the issue has already been mentioned.
Quick Links:
📓 Bug Tracker Guidelines – 💬 Community Support – 📧 Mojang Support
📓 Project Summary – ✍️ Feedback and Suggestions – 📖 Game Wiki
-- I am a bot. This action was performed automatically! The ticket was resolved by one of our moderators, and I left this message to give more information to you.