I'm having the same issue on Xcode 12, beta 3. The widgets in my project don't load when installed via Testflight, I cannot even add widgets. This also happens to me when using Ad Hoc distribution, so it's probably not an issue with TestFlight but a distribution issue.

I'm having the same problem, i.e. https://developer.apple.com/forums/thread/656958

@LualdiD, I've found a solution to this issue. Following from the newly added documentation, https://developer.apple.com/documentation/bundleresources/information_property_list/nsaccentcolorname While you can set this directly in your Info.plist, the recommended approach is to use the Global Accent Color Namebuild setting (in the Asset Catalog Compiler - Options section) of the target. Set the value of the build setting to the name of the Color Set in the asset catalog. Xcode automatically sets NSAccentColorName to the appropriate value in the Info.plist file when building your project.  It looks like Xcode automatically adds the NSAccentColorName key to watchOS plist when building. To avoid this, I've unset the ASSETCATALOGCOMPILERGLOBALACCENTCOLOR_NAME on the Xcode build settings for my watch os related targets. Since I use xcconfig files, I set ASSETCATALOG_COMPILER_GLOBAL_ACCENT_COLOR_NAME = , i.e. empty, in my parent watchOS.xcconfig file.

 I've found a solution to this issue. Following from the newly added documentation, https://developer.apple.com/documentation/bundleresources/information_property_list/nsaccentcolorname  While you can set this directly in your Info.plist, the recommended approach is to use the Global Accent Color Namebuild setting (in the Asset Catalog Compiler - Options section) of the target. Set the value of the build setting to the name of the Color Set in the asset catalog. Xcode automatically sets NSAccentColorName to the appropriate value in the Info.plist file when building your project.  It looks like Xcode automatically adds the NSAccentColorName key to watchOS plist when building. To avoid this, I've unset the ASSETCATALOGCOMPILERGLOBALACCENTCOLORNAME on the Xcode build settings for my watch os related targets. Since I use xcconfig files, I set ASSETCATALOGCOMPILERGLOBALACCENTCOLORNAME = , i.e. empty, in my parent watchOS.xcconfig file.