Xcode 12 ProcessXCFramework fails to copy headers on build

I'm trying to build and run my app from Xcode 12 but the ProcessXCFramework step fails telling me that it could'n't copy the headers from my xcframework files :

Code Block 
ProcessXCFramework /Users/username/xyz_no_spaces/libgpg-error.xcframework (in target 'MyApp' from project 'MyApp')
		cd /Users/username/xyz_no_spaces/MyApp
		builtin-process-xcframework --xcframework /Users/username/xyz_no_spaces/libgpg-error.xcframework --platform ios --target-path /Users/username/Library/Developer/Xcode/DerivedData/MyApp-gyqvfqslpvdvpubdhccubciywesh/Build/Products/Debug-iphoneos
error: “gpg-error.h” couldn’t be copied to “Debug-iphoneos” because an item with the same name already exists. (in target 'MyApp' from project 'MyApp')

Note: the file does not already exist at the target path (or maybe it's just deleted after it fails, I don't know..)
I get this message for all 6 of my xcframeworks which are all set to 'Do not embed'. Works fine on Xcode 11. So I guess it's either an Xcode 12 bug or I need to check a box somewhere when moving to 12.

I've tried removing the frameworks completely and re-adding them. Nuking the DerivedData folder and recompiling from scratch. No love. :(

Has anyone found a workaround for this?

In case my frameworks are somehow malformed (I did merge ios-x86_64-maccatalyst dylibs into them back in the day, but removing them makes no difference) maybe someone can spot what's wrong with this example file structure:

Code Block 
libgpg-error.xcframework
	Info.plist
	ios-armv7_armv7s_arm64
		Headers
			gpg-error.h
		libgpg-error.a
	ios-i386_x86_64-simulator
		Headers
			gpg-error.h
		libgpg-error.a
	ios-x86_64-maccatalyst
		Headers
			gpg-error.h
		libgpg-error.a

Lipo -info on all of the dylibs match the architectures in the folder names. (And has worked fine for the last year using Xcode 11.)
The info.plist:

Code Block <?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
	<key>AvailableLibraries</key>
	<array>
		<dict>
			<key>HeadersPath</key>
			<string>Headers</string>
			<key>LibraryIdentifier</key>
			<string>ios-armv7_armv7s_arm64</string>
			<key>LibraryPath</key>
			<string>libgpg-error.a</string>
			<key>SupportedArchitectures</key>
			<array>
				<string>armv7</string>
				<string>armv7s</string>
				<string>arm64</string>
			</array>
			<key>SupportedPlatform</key>
			<string>ios</string>
		</dict>
		<dict>
			<key>HeadersPath</key>
			<string>Headers</string>
			<key>LibraryIdentifier</key>
			<string>ios-x86_64-maccatalyst</string>
			<key>LibraryPath</key>
			<string>libgpg-error.a</string>
			<key>SupportedArchitectures</key>
			<array>
				<string>x86_64</string>
			</array>
			<key>SupportedPlatform</key>
			<string>ios</string>
			<key>SupportedPlatformVariant</key>
			<string>maccatalyst</string>
		</dict>
		<dict>
			<key>HeadersPath</key>
			<string>Headers</string>
			<key>LibraryIdentifier</key>
			<string>ios-i386_x86_64-simulator</string>
			<key>LibraryPath</key>
			<string>libgpg-error.a</string>
			<key>SupportedArchitectures</key>
			<array>
				<string>i386</string>
				<string>x86_64</string>
			</array>
			<key>SupportedPlatform</key>
			<string>ios</string>
			<key>SupportedPlatformVariant</key>
			<string>simulator</string>
		</dict>
	</array>
	<key>CFBundlePackageType</key>
	<string>XFWK</string>
	<key>XCFrameworkFormatVersion</key>
	<string>1.0</string>
</dict>
</plist>