The phrase "unrelated note" means a piece of information or a topic that is different or not connected to the main subject being discussed. Full definition
On a completely unrelated note, I think that when we embrace and are more conscious of other cultures, we become more inclusive people. (melinspired.com)
On a totally unrelated note, those jeans look amazing on you! (witwhimsy.com)
And on a slightly unrelated note, do you have any links to resources about dry - nursing during pregnancy? (wendywisner.com)