DAX IF Statement producing errors highlighted in red font

Thanks,

I've hit Enter at the bottom of the Formula Box and nothing happens? Everything is Grey all the way to line 14 but despite this the column has been populated by dates - so could I assume that everything is working and just ignore the red?

Also, the TRUE values such as Assessment, Casework Support etc are the same named values that exist in another table called 'Stage and Area', I'm not sure how that could affect this calculated column as we are in a different table?

Lastly, as this column contains dates that depend on the logical test being TRUE or FALSE, the column was created in the Cases - Active table to compute this. There is no measure icon for this column anywhere.

If you are suggesting this is a measure then should I be seeing this as Meaure in the field bar instead of a Date icon?

Unless I explicitly click on New Measure I cannot see how a measure be created by accident?

Thanks for being patient!