Hi,
I don't have the answer, but...
I find it interesting that you would use your own editor on a Theme hook. I would agree that using your own editor on a Code hook is far more convenient than using adminCP editor, but for a Theme hook ??? Personally, I find the adminCP editor more convenient as it sorts out all the escapes (among other things). What motivates you to use your own editor?
Secondly, if this used to work before 4.7.16 and if you have NOT made any changes to your editor (either configuration or version update) then I can understand your point of view - that it should not have been broken.
That said, the Invision comments say "do not remove" and that implies "do not modify, either" and your editor has clearly modified the lines - what was '/*comment*/' is changed by your editor to '//comment' which is not the same thing.
John
