That was prior to Alexander's planning for a war against France. Also of note is the failure of the Russians to support France against Austria in 1809 as they had agreed to do. They sent an army into Poland, but it did little fighting and did interfere with Poniatowski's operations. That isn't the conduct of an ally, but of an enemy. Further, Alexander wanted the Duchy of Warsaw under his rule and authority and made aggressive moves against the Poles, who rebuffed his actions as they were loyal French allies.