Application does not select correct language from system settings MacOS Catalina

I have installed GPXSee for Mac (https://www.gpxsee.org) 

GPXSee

Versão 7.19 (x86_64, Qt 5.9.7)

The problem is that the application is using the language localisation of Portuguese which is way down on my list of languages in the System Settings. The author of GPXSee says that there are 4 supported languages at the top of the list including English and Norwegian that should have been selected before Portuguese.

I tested pruning the list of languages from the System Settings list removing Portuguese, Chinese etc With only 5 languages in the list, Norwegian was selected. Since this issue only affects GPXSee (and perhaps OpenSCAD, but that is not reproducible now) we suspect Qt to be the owner of the bug.

The attached screen shot displays my top languages in System Settings and the Portuguese speaking GPXSee in the background.