Yes, it's been an issue for some time, but peope usually stop the quote when it gets too long, so it's not too rampant.
Just keep nesting quotes until you've got more than 5, and you'll notice they stop alternating between grey and blue, like so:
The colours to keep alternating.
I've seen it often between other users' conversations, and since most use the BBCE, I'm almost 100% sure it's not related to which text editor is being used.
Assuming you have access to deleted threads: