If your app is published as a Custom App (as most of ours are) and therefore not visible on the App Store, using redemption codes from Apple Business Manager (versus relying on Managed Licenses) also allows the app to launch. This may be a temporary option for business users that have already upgraded to iOS 14.2 and cannot launch apps distributed via MDM using Managed Licenses. Obviously with a large number of users this may be prohibitive, but with a relatively small number of users sending them redemption codes may be an option.

Submitted FB8907917 with symbolicated crash log, sysdiagnose and other info requested by Jason @ Apple below. https://feedbackassistant.apple.com/feedback/8907917