BUG in Perspective timezone handling

As far as we can make out, the Perspective Project Timezone property in Project Properties has no effect.

Any date function run in a script or an expression runs on the gateway and returns a UTC time, whereas anything displayed on the client in a date aware control (like a DateTime Input) is altered to match the client timezone.

This is in contrast to the Vision Timezone Behaviour project property which works as advertised.

How can we ensure all Perspective clients display gateway times?