Variable file rejected if it contains variables with a hyphen or space in the name

This is my second attempt to use variable files, as I struggled to figure out why Ride would not accept my file. After some experimentation, it seems Ride does not like variables within a variable file to have hyphens (or spaces) in the name. This is confusing as it allows hyphens and spaces in variable names that are created elsewhere.
E.g. this code in a resources file works:-

 *** Variables ***
 ${ID-Prefix}

Also the documentation in RF (https://robotframework.org/robotframework/latest/RobotFrameworkUserGuide.html#variables) does not specifically warn against using hyphens (using only alphabetic characters from a to z, numbers, underscore and space is recommended...).

I am not sure if this is a RF or just a Ride issue, but I am hoping it can either be fixed, or the documentation updated to reflect the limitation.

Many thanks

Start by reproducing the reported variable-file failure with names containing hyphens or spaces, then compare it with the working resources-file example. Trace whether parsing belongs to RIDE or Robot Framework; done means either variable files accept these names consistently or the limitation is clearly documented.