Here is a simple text, that I want to convert to comment:

-- begin
/*O*/ test -- ID's
/*N*/ test -- Syntax: 'test'
-- end

If the entire text is selected and then changed by using [Edit|Selection|Comment], you will get the following result:

/*
-- begin
\*O*\ test -- ID's
/*N*/ test -- Syntax: 'test'
-- end
*/

It seems that the comments in the line are misinterpreted.

tested with v13.0.1 (32) w10

In v12 is works correctly, btw

This does indeed not seem to work as expected. We'll fix it.