Your comments

Didn't we add a rule a while back that a map/scenario has to be completed once "normally" before mutators/god mode can be used on that particular scenario (so the first playthrough is always as the map creator intended it to be)?

Could it be related to that?

In the mean time, you can always use the cast spell function to cast Prophecy on the target area for a temporary reveal.

Huh looks like something is definitely wrong there then. @Cian needs to re-open the ticket.

Have definitely you created a number variable first ready to use?

EDIT - Can you screenshot how the action screen looks?

You need to use [0] which is a reference to the variable itself (if it was a list of variables it would be the first variable in the list and [1] would be the second variable in the list)

So you literally need to try: "Your text here [0] more text here" and the [0] gets replaced into and displayed "Your text here 1 more text here"or whatever the variable number.

As for where I got the information, there is no tutorial (yet). I know because I helped test MightyScript before it was released and this is one of the things I worked with Nano to get working properly.

You need to pick a variable as well as choose the text that displays with it. As per my example above "Your Number is [0]". the [0] is the bit you picked with the pick item button, but without actually adding that to the text to tell the game I want my variable to be here, there is nothing to display.

How were you displaying the Number?

You usually need to display it as something like "Your number is [0]" with the [0] getting replaced by the actual Number variable.

Sounds like the save file got corrupted and the UI failed to display due to an exception trying to read a corrupted file?

Double check that Windows hasn't muted the game's volume (it's happened to others for seemingly no reason), you can check by right clicking the volume icon in your task bar and opening the mixer to see each individual volume for different things.