I don’t think it makes any difference how you create your target String type Item.
Your problem does look the same as @Cybso , although you’ve not shown us the crucial part - the profile you selected for your channel link.
@Cybso did not find a fix for this problem,but a circumvention (doing the transformation elsewhere)
The nature of the problem appears to be that the transform profile framework attempts to use a binding supplied default state presentation format on the output of a transform.
This blows up when a numeric channel’s format is used on a string output.
Not all bindings supply a default state presentation format for any given channel, so it’s not an obvious problem.
There is an open issue (bug) which is about all this but originating from a different profile type
so hopefully it will get fixed in the framework at some point.
Meantime, the workaround is to use two Items and a rule that transforms from raw numeric Item to alpha Item.
