I've a date column messed up with different date formats how to fix it in power bi

Column = 
var left_ = LEFT('Table'[Date],2)
var mid_ = MID('Table'[Date],4,2)
var right_ = RIGHT('Table'[Date],4)
var Month_ = IF([Index]<MAX([Index])/2,[Date],mid_&"/"&left_&"/"&right_)
return
Month_