$1 showing up as bad field name in variable

[sri_c003]

So this was working before, like last week. But now, with the same version of Qlik Sense desktop - September 2017, it is showing $1 as bad field name. Even more troubling is the fact that a perfectly working application last week is not working now 'cos of this error.

Example variable: if ($1>1000, 'more than thousand', 'less than thousand')

I use this in the expression field, considering the variable name as var1, as $var1(640), and it was working. But now it isn't working, and is showing "bad field name" for $1.

[sri_c003 · Accepted solution]

Additional observation:

The "edit expression" box shows all $1 as bad field names, but when applied on UI, it is calculating value properly.