I experience this too and I think it has been mentioned before.
If my ancient mind recalls correctly, it is the result of a development Dave provided at the request of users which did not have the correct voices and words available. There is a way of turning it off and reverting to the old system - I'm not sure if I am right here, but you might find that turning off "Use QNH instead of Altimeter for non-US" will avoid this if it is irritating. That is in Options 1, under Misc Options.
For myself, I have got used to it.
John