Android: input method events not delivered until keyboard shown at least once

With an android device https://www.datalogic.com/deu/einzelhandel/mobilcomputer/memor-1-pd-844.html it's possible to scan bar codes. The bar codes are received as QEvent::InputMethod.

The problem is that with this device the input method events generated by scanning a bar code BEFORE the android keyboard is displayed at least once seem to be entirely missing. After displaying the android keyboard the events triggered by scan are received as per usual.

steps to reproduce the problem:

1. open the app
2. scan a barcode => nothing happens
3. activate the keyboard by tapping on the input field
4. scan a barcode => code added to the input field

NOTE: the keyboard does not need to remain open for scanning to work. I just needs to have been opened at least once.