I believe in some other cases Russian and Allied where nearly engaging.
I rememeber having read an account - I do not remember if it was Johnnie Jonson's or Pierre Clostermann's - The accounts tells he was flying over Berlin, and a formation of Yak tryed to move on their 6 o clock. In the book he tells he cannot accept this, and the two formations - RAF and VVS - were manuevering in order to get the best firing position. Then the Russian decided to break.
The source must be, as far as I rememeber, one of the final chapters of one of the following two books:
Jhonnie Johnson - Squadron Leader
Pierre Clostermann - The big circle