From what I understand, you have submitted a self attested role and responsibilities letter with an LOE. I do not think you should be worried then.
The person who got rejection did not submit anything. Only slips, offer letter etc. No mention at all of role and responsibilities. Now that is a red flag. CIC explicitly states your R&R should be available since you are applying under a specific NOC.
But in your case, the letter is available (only not on letterhead or by a colleague). Don't worry, it should be fine.
PS I have a friend who has got her PR in a similar situation.