There is a bug in iPadOS 15.x where the keyboard will stop appearing in any PWA on the device.
The bug can be produced by launching a PWA and removing it from history (double tap home and flick it away) and relaunching it. At that point the keyboard will not appear in the PWA when selecting an input element or in any other PWA. The bug reproduces using sites like bmw.com and starbucks.com when installed and then launched from the Home Screen. The only remedy I've found is to clear Safari history in settings. ♂️.
Are there any client-side work-arounds to this issue?