Well, i would've just done it with actions in the talk animation part. Something like
Set istalking to true
Wait till person has finished talking
Set istalking to false
And then just tell the idle animation to if istalking = false etc etc
Although this will probably give me the same problem since the interruption is still there

I think the problem is, that my timer which picks a random value doesn't stop when the talk animation plays so while she talks, the timer runs out in the background and already starts the random animation which will flash inbetween textblocks. Maybe i should try to reset it while she is talking or something...