I had never problem with separation on my Tele-Rolleiflex but I did have problem with separation with not one, but TWO Rolleiflexes Planar 2.8. I had them both re-cemented by a very skilled optician and my impressions are mixed: one was ok - looking at pictures you couldn´t tell the lens one day had a separation - but the other never again achieved a good result and the camera was disassembled for parts.
From my experience, it´s a lottery (is there this expression in english?) where you may win or loose.
Now I purchased a Voigtländer Bessa II with Heliar lens almost entirely separated and I took a few pictures with it before disassemble the lens but I didn´t have them developed yet to see what effects the separation causes.