To make things clear the problem is NOT with brace highlighting, it is with Batch lexical analysis.
Brace highlighting only works for the same lexical type of the language.
Put the following into a C file and check which brace is highlighted. Then change the language to normal text and check how it changes.
If you observe the lexical types of Batch in Style Configurator you will see two relevant types: Command and Default.
Based on coloring (without higlighting) you can see that most of the braces are Command except for the one after the ELSE that is Default so it is not matched with Command braces.
So what you want is the Batch lexer to be fixed so a brace after else becomes Command (or all others become Default).