WAHWAH

I quite liked my tyres up to 17000 miles when I noticed a bulge on the sidewall on two of them. Both bulges were in exactly the same place on the tyre wall, on the ‘N’ of the word Geolandar.
A Subaru technician inspected them and noted that apart from the bulges there was no other sign of damage or marks that would indicate a kerb strike or similar and it looked likely to be a manufacturing defect, and I certainly have not hit anything to my knowledge. The tyres were further inspected before removal by a tyre agent who also made the same comments. The tyres still had 5mm of tread so were wearing remarkably well. The tyres were duly changed and both were sent to Yokohama for warranty assessment with a covering note. A month later I received a standard letter reply stating the damage was likely caused by obstacles such as stones, pieces of glass nails steel plates etc, and further went on to suggest that I drive more carefully avoiding such obstacles. As if we aim for them!
I was naturally outraged and disappointed and now would ask Subaru if these tyres are suitable for the purpose of being fitted to such a car. What do you think?