"Clang-Tidy and Clazy" analyzer reports wrong number of file analysis failures

I am using the "Clang-Tidy and Clazy" analyzer to run clazy on most of the files of my project. Once the analysis is complete, the "Clang-Tidy and Clazy" view that shows the diagnostics as a tree shows a warning at the top: "Failed to analyze 1 file(s).".

If I click on this linked text, the output pane is opened, and the end of the output indicates that 609 files were not analyzed:

06:11:10: Error: Failed to analyze 609 files.
06:11:10: Clang-Tidy and Clazy finished: Processed 2035 files successfully, 609 failed.
06:11:10: Elapsed time: 14:10.

Looking through the full output of the analysis, I see a bunch of failures that look like this:

Failed to analyze "D:/src/igor10/igorsrc/COM/COMDataFolder.cpp": Clazy finished with exit code: 1.

and also a bunch of failures that look like this:

Failed to analyze "D:/src/igor10/igorsrc/Generic/IgorString.cpp": Clazy crashed.

To be clear, the bug I am reporting is not the failure to analyze files or the crash of clazy but the failure to properly report the number of files that could not be analyzed in the results view (circled in red in the screenshot above).

FWIW I'm building with Qt 5.12 and VS 2017. In the Clang Tools setting pane in Creator, parallel jobs is set to 28.