I just tested this on Samsung Note 4 and you are absolutely correct that the scanning windows is too small. I ran the sample BarcodeScanner app with the latest (1.2.9) version of the plugin. The issue comes from this commit
to the BarcodeScanner 1.2.4 version. The MAX_FRAME_WIDTH
properties are changed there. This means that, with prior to the 1.2.4 version of the BarcodeScanner plugin, the issue should not be present. However, I will escalate the matter to our development team in order for a fix to be applied as soon as possible. Meanwhile, what I can suggest is to change the MAX_FRAME_WIDTH
properties, as described here. Note that, you will have to re-build the zxing library for the changes to take effect.
I hope this helps.