Stylus (e.g. wacom) input has incorrect offset
When creating an annotation using a stylus (such as for example using a laptop with a wacom enabled display), the input is offset. The error shows up in at least 0.4.2 (which is the most recent i've got access to).
The following was done by attempting to draw lines originating from the top left corner of the image and then down and right respectively:

What OS are you using? Is this just a notebook monitor where you can draw with a wacom pen or do you have an external device connected to you notebook, probably the former?
i'm on openSUSE Tumbleweed (the package is from the official openSUSE-Tumbleweed-Oss repository). And yes, the former - specifically it's a Dell XPS 13 2-in-1 9310, which translates to a Wacom 48EC tablet (though i imagine it'll be the same for any Wacom display type thing) :)
What Qt version do you have installed? Could it be related to this Qt Bug https://bugreports.qt.io/browse/QTBUG-77826
i'm running 5.15.2