I have this issue as well, the ToggleSwitch is an uncontrolled component and does not listen to its modelValue, which is bad practice

Originally posted by @stam in #6961

Here is the updated stackblitz repro with Primevue v4 and Vue + Vite.

Try clicking the element. The model ref stay false while the component changed into checked state, which supposedly to stay unchecked and consistent to provided modelValue state.