As of the open beta update (beginning of January), Synapse overrides the expected behaviour for the ‘Escape’-Key in Hypershift on my Huntsman V3 Mini (german layout). I has worked properly up to that point.
This would be [^] for fn+ESC and [°] for fn+shift+ESC. Instead the overlay in Synapse shows [`] and [~], though it activates neither of them upon pressing the button and acts as ESC. The result being, 2 needed keys are currently inaccessible.
This is a Synapse specific issue, since it works properly once Synapse Beta is not running, or the keyboard is used on a PC that does not have it installed at all.