The MouseArea seems to have gotten a lot "slower" since Qt 6.2.4.
With Qt 6.2.4 one could click the MouseArea quickly and still receive the signals released() and clicked() consistently.

Since Qt 6.3.1 this seems way slower and actual (physical) clicks get lost.
See the attached minimal example to reproduce the varying behaviour.

The example consists of a MouseArea filling the entire screen and counters for the pressed(), released(), and clicked() signals. When "clicking" the MouseArea somewhat fast, one can see that the counter for pressed() increases as expected, whereas the counter for released(), and consequently, clicked() do not (they increase more slowly).

When using Qt 6.2.4 these counters stay in sync.