Yes, Marc (Multiweb) explained this to me earlier in the year.
At the time I was comparing M33 data we both shot at Qld Astrofest through FSQ106s. My data with QHY9 (with microlenses), and Marc's with QHY8 (without). Concerned why my FSQ had diffraction spikes!
Example image here:
https://picasaweb.google.com/UserRob...66930876545234
(left is super zoomed in QHY8, right is same FOV QHY9)