Here is a recording of the warning
The Turkish airforce warning - according to this clip - includes the phrase "...on Guard" which we will probably take to mean 121.5. If the Russian crew were not on that frequency then they will not have heard it. Also it was transmitted in English and I'm not certain that all Russian mil pilots have a complete command of English.
The questions are therefore did the crew have the equipment and knowledge to receive this warning and did they knowingly cut through the tiny piece of Turkish airspace?