There is a new, amended, version of the POS app available in the Apple App store that contains a resolution for the mPOP all in one printer issue that you have been experiencing.
To download version 5.46.1, you may need to go into the App store and search for the Shopify POS app and enter the details page to see the option to download. Here is a link directly to the app page
Apple does implement a phased rollout for new app versions, so if you do not see app version 5.46.1 in the version history of the app details page, you may need to do one of three things:
If the issue persists or returns, please continue to use the previous workaround and let me know immediately.
Thank you again for your patience.