Feedback from several testers over the past few days suggest that d2 or d3 was the strongest version and that since then the progressive updates have weakened overall performance. My understanding, is that there are 2 parallel streams of development underway. The last "official" release of Robbo by the engine author was 0.085d and the official site of the engine author is this one, of which the originating language is a mystery. There seems to be a mix of languages and odd translations if you look around the site which are not necessarily related to Russian:
http://ippolit.wikispaces.com/In parallel there are a group of Russian programmers who are "unoffocially" tweaking the code to try to find improvements whilst waiting for the next official update (allegedly the mp version) and this has led to the succession of releases in the "d" series. These releases are being posted on the chesslogik site:
http://www.chesslogik.com/robbolito.htmwhich is the site belonging to one of these Russian programmers (known as Kranium) and is not the Robbo author's site. One of the things this group has introduced is variable UCI engine parameters which the original release did not have. If you look at the latest versions you can see there are now engine parameters that can be adjusted. These are all around fixing a ponder issue and "Flexible Time Management Options" - to allow adjustments for different time controls. I suspect that these tweaks and changes have somehow weakened the performance and caused the issues you have found. I have pasted below the explanation given for these parameters:
NTM (Normal Time Management) - is a variable used to determine the move time for blitz (it divides the max time) and is the original algoritm from Robbo 0.084 through to version d3. It is used only if the NTM check box is 'checked'. This can cut the timing very fine so careful adjustment of the NTF is needed if NTM is enabled. NTM has now renamed OTM (Original Time Management) for clarity.
NTF (Normal Time Factor) is a variable used to determine the move time for blitz (it divides the max time) . NTF is divisor for Normal TM (used in 0.084 up to version d3). NTF has now been renamed OTF (Original Time Factor) for clarity.
The corresponding code is TIME_DESIRED = TIME_MAX / NTF + INCREMENT; - so the lower the number is, the more time per move.
ETM (Enhanced Time Management) - is a variable used to determine the move time for blitz again, it is a divisor...the lower the number, the more time per move from Robbo versions d4/d5 onwards.
ETM is the default...if nothing is checked (or if both NTM and ETM are checked) then the engine uses ETM
ETF (Enhanced Time Factor) is a variable used to determine the move time for blitz again, it is a divisor...the lower the number, the more time per move. ETF is divisor for Enhanced TM used in Robbo versions d4/d5 onwards.
The corresponding cod is ( (TIME / 25) > INCREMENT ) TIME_DESIRED = (TIME / ETF) + INCREMENT / 4;
MOPH (Move on Ponderhit) ..the engine will move immediately if it was pondering the correct move. i.e. the predicted move is actually played by the opponent...this saves up valuable time for later moves.