The correct font weight is not rendered when loading the Roboto fonts from a QRC file using QFontDatabase and then displaying that text using a Text QML item. This was working fine in 5.15.4, but is now broken in 5.15.5 on Windows version 20H2.
I have attached a simple QtQuick sample program to demonstrate the issue. All it does is load the Roboto fonts from a QRC file using QFontDatabase in main.cpp, output the loaded font families using QFontDatabase::applicationFontFamilies to ensure that the fonts were loaded correctly, display a simple QML file with two Text items both rendering Roboto font with one bold and the other regular weight, and then output the Text font family/weight/bold info once the Text items have completed creation. The output is identical on both 5.15.4 and 5.15.5 with both indicating that all fonts have loaded correctly and the Text item has the expected family/weight/bold info. However, on 5.15.5 the Text item with bold set to true is rendered as thin text even though everything indicates it should be bold. Please see the attached photos and sample application.