If you have a fixed format cobol file, having any text in columns 1-6 will cause the highlighter to ignore a comment on column 7.
```COBOL 123456*DO-SOMETHING. ```
Would not be highlighted as a comment, for example. Whereas,
```COBOL *DO-SOMETHING. ```
Would.
I assume there's an assumption that if anything is in columns 1-6, then it's not a fixed format.