In my plugin the user may use VAD as configured in The TS3 Client options dialog. Nevertheless, in a specific situation I have to use a soft PTT triggered by the message WM_LBUTTONDOWN. As suggested in the documentation I disable VAD when the situation appears with:
ts3Functions.setPreProcessorConfigValue(ServerID," vad","false");

then, when WM_LBUTTONDOWN arrives:
ts3Functions.setClientSelfVariableAsInt(ServerID, CLIENT_INPUT_DEACTIVATED,INPUT_ACTIVE);

ts3Functions.setClientSelfVariableAsInt(ServerID, CLIENT_INPUT_DEACTIVATED, INPUT_DEACTIVATED);

When the special situation ends, I activate VAD again with:
ts3Functions.setPreProcessorConfigValue(ServerID," vad","true");

The soft PTT works fine, but the error is, that VAD does not work anymore. The blue LED in the client window is not illuminated if I talk into the MIC. I have to restart the client to activate the VAD again. Is this a known bug or am I wrong with my logic?