Occasionally, I can see clangbackend process starting to continuously consume 100% of one CPU core. When this happens, QtCreator stops applying code coloring in the editor. This situation does not recover by itself, I have to restart QtCreator or kill clangbackend so it is restarted.
I do not have a reliable way to reproduce the issue, it just happens at random times while I'm editing C++ code, most often template function bodies. I cannot create a small reproducer project.
I've attached a bactrace of clangbackend during one of these busy loops.