Problem with replays on the state machine's transitions.

I have this state machine in one of our Animator Controllers.

The problem is that every time we change from Defend/Upset/Angry/AttackAngry to Attack Unity plays the Attack clip and then, inmediately plays again for one second the last clip played before Attack, and sometimes the two last clips... and that behaviour is not fired by code. We change from one state to another by setting a trigger depending on a condition except in the transition Attack to Waiting that changes depending on the ExitTime. Almost all the transitions are similar to this one:

And if we debug that behaviour (the replay of the last clip) is not because of a trigger, Unity plays a part of the clip/s by itself. What is wrong? I hope I made myself understood since english is not my native language

Thanks in advance