What you've shown does not exactly match your description. An XOR (symmetric difference) operation (per the FAQ) would leave @final = ( t3, t5, t7, t8 );. Ie. Those elements that appear only in one or the other array but not both.

To achieve what you've shown (and described except for the XOR reference), you could do

C:\test>p1
@array1 = qw[ t1 t2 t3 ];;
@array2 = qw[ t1 t2 t5 t7 t8 ];;
@seen{ @array1 }=(); 
@final = grep !exists $seen{ $_ }, @array2;;
print "@final";;

t5 t7 t8
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