Try logic doesn't work for invalid tags in expressions

It looks like invalid tags don’t resort to the failover case when using the try statement.

You can either look at the quality value of the tag in an if block or use the forceQuality function.

The quality of the tag will still not exist if the tag doesn’t exist…

No, it does have a quality which is 300. For example:if(toInteger({Sine/Sine10.Quality}) = 300, toDouble(-2), toDouble({Sine/Sine10}))

So quality is assumed even if the tag is does not exist?

Yes