A33
I seem to remember that I had the same problem, early on, with the Spaun and changed it one of the BESTs, with no improvement - won't be taking it up with Spaun themselves as I have probably had it for over 10yrs.
With respect to the distances, the EMP and 2 of the BESTs were within a couple of feet of each other, and the other BEST was about 8-10m away, so I don't think that was a contributory factor.
With respect to the receiver repeating the commands, I don't know if it does or if it does not, although I did note a consistent, about 5-10 secs apart, spike on the signal strength meter when that was connected just in front of any of the switches (EMP or BEST) - regardless of whether there was actually some sort of sat signal present or not. That might have been repeated Diseqc commands, or something else (never noticed the same thing with the old Icecrypt).
As far as the Opticon is concerned, from experience a few weeks ago, that is 1.1 and can supposedly be changed to an uncommitted switch - but only if you can get the (literally, unless you are prepared to buy 1000's of them!) unobtainable programmer to do it, so it is stuck were it is. Because it can't be changed then it cannot be cascaded (IIRC I tried that) and that was the reason for getting the EMP which can be physically switched between modes (or so I understood!).
Anyway, at this point I am getting very, very fed up about spending a lot of time (many days) and money getting almost literally nowhere, and so am going back to a more restricted setup that I know (probably still !) works, and so that I can get on with a lot of other things that need doing (badly).