Had same problem with mine, so took it to the dealer who advised me that it was the cam timing, which, apparently, is a common problem with 999bp, 999s and 749s which is usually sorted at 1st service!
We can sort that out for you sir, just need the bike and to relieve you of around £130!!!!
Previous owner ran Termis so never had the problem, and never needed to have the timing reset, and as its an '03 wasn't covered by the warranty!
Anyhow, i paid the man and took comfort in the thought that it was no longer going to cut out at completely random intervals. Went to pick it up two days later and on the journey home..........yup! you guessed it.......pthaaaah! cut out at a roundabout and with all its Italian "character" wouldn't re start straight away!
Its been back and still does it, so, in my opinion, i was left with only two choices, and this is my advice to you:
Have just finished fitting the Termis today so here's hoping no more embaressing or dangerous moments!