XnView Software

XnViewMP 1.4.3 64bit
Windows11 (22H2), display resolution 3840x2160, win scaling 150%

Batch convert
'Extract channel' extracts nonexisting Alpha

To reproduce:
1. run clean portable XnViewMP
2. open any image without Alpha channel*
3. press CTRL+U to open Batch convert
4. add 'Extract channel' action
- set Alpha channel
preview will show some data (same as Red channel)

* no bug on 8bit png

Thanks to your detailed description I can reproduce

See issue for current status and some details.

This problem is supposed to be fixed in XnView MP 1.5.0 beta. Please check and confirm the bug fix here.

fixed in 1.5.0b1