Qt Creator becomes stuck in an infinite cmake loop if cmake-project uses doxygen

When my cmake project uses doxygen, especially the doxygen_add_docs command, then qtcreator gets stuck in an endless cmake loop.

Steps to reproduce: 

• create a cmake project using doxygen and doxygen_add_docs or consider the attached example project
• the first "Run CMake" is ok
• Observe that all other cmake runs (either from "Run CMake" or triggered by saving one of the CMakeLists.txt files) let qtcreator get stuck in an infinite cmake loop where it is running cmake without end.
  You need to comment out the doxygen_add_docs command in in doc/CMakeLists.txt and save it.
• observe that it is related to the application having the focus:
  • the loop is happening as long as qtcreator has the focus
  • when you change focus to another app the loop pauses
  • the loops continues when qtcreator gets the focus back
• when you have commented out the doxygen_add_docs command:
  • activate it again by removing the comments, save the file
    • observe the the first (automatic) cmake run works
  • make a change to that file and save again
    • observe that we are again stuck in the infinite cmake loop

My cmake version is 3.16.3.