Its good that they are going to replace it Rob. Especially with small taps you have to be careful not to put any sideways pressure on them as you cut the threads. Tapping close to an arc weld can be a problem too, as if it has cooled a bit too quickly it can form what we used to call "diamonds" in the metal, seen even hi speed steel taps have problems with those.
Bill
(Who has broken 3/4" taps in his time
)