When akonadiserver and Kontact are running, akonadiserver takes a near-constant 8% of CPU time (100% of 1 CPU thread) and accumulates 10,560K of heap memory per second. Quitting Kontact does not stop the memory leak. If I stop the akonadiserver process itself, the leak stops and the memory is recovered.

Also, when akonadiserver is accumulating memory and taking 8% of the CPU time, some file operations run very slowly. File managers take about a minute to load, as do dialogs to save files from apps. Once akonadiserver is ended, file operations return to normal.

inxi also stalls during execution when akonadiserver is accumulating memory, saying that it cannot start a freedesktop.org service, but inxi works once akonadiserver is stopped.

I tried checking the Akonadi.error log, but the only error noted is from stopping akonadiserver:

"Qt has caught an exception thrown from an event handler. Throwing exceptions from an event handler is not supported in Qt. You must not let any exception whatsoever propagate through Qt code. If that is not possible, in Qt 5 you must at least reimplement QCoreApplication::notify() and catch all exceptions there."
I believe that all this started with the update to KDE Plasma update 5.22.0. I tried renaming .local/shared/akonadi and then restarting Kontact, but that didn't help. Any other ideas?