CMake error in Qt5BootstrapConfig.cmake

Trying to compile a project the first time with Qt 5.15.1 I get the CMake error:

CMake Error at /opt/Qt5.15.1/5.15.1/gcc_64/lib/cmake/Qt5Bootstrap/Qt5BootstrapConfig.cmake:14 (message):
The imported target "Qt5::Bootstrap" references the file

"/opt/Qt5.15.1/5.15.1/gcc_64/include/QtCore QtXml"

but this file does not exist. Possible reasons include:

• The file was deleted, renamed, or moved to another location.

• An install or uninstall procedure did not complete successfully.

• The installation package was faulty and contained

"/opt/Qt5.15.1/5.15.1/gcc_64/lib/cmake/Qt5Bootstrap/Qt5BootstrapConfig.cmake"

but not all the files it references.

Call Stack (most recent call first):
/opt/Qt5.15.1/5.15.1/gcc_64/lib/cmake/Qt5Bootstrap/Qt5BootstrapConfig.cmake:177 (_qt5_Bootstrap_check_file_exists)
/home/prh/projects/gen4-trunk/qt5/CMakeConfig.txt:53 (find_package)
CMakeLists.txt:1168 (INCLUDE)
CMakeLists.txt:1256 (dummy)

With Qt 5.12.4 and CMake 3.13.4 it worked well.