Bridgestone Front tyres/tires - Unusual stress fault

I am seeing a fine cracking on the outside tread of the front tyres. The cracks are in the outer tread blocks and comprise numerous fine lines.

I feel sure this reflects the tall nature of the tyres combined with a narrow contact patch. Seems that the cornering forces are causing the outer rubber blocks to develop thin fracture lines.

So far it does not look to be an issue and the tyres seem to be wearing down normally but has anyone seen this develop into something worse, e.g, actual tread break up?

Heat and age affect the rubber...so, look at the number stamped in the sidewall to determine when the tires were made. If you live in an area where it is extremely hot, that will also affect the rubber. You might want to go to a Bridgestone dealer and have them look at the tires. They can help you determine the date of manufacture or if it is a real problem, or just one attributed to the age and environment.

Industry wide general recommendation on tires is to replace them at 6-years maximum, regardless of the tread depth, because the tread gets harder and less resilient as it ages, leading to cracks. Extreme heat speeds that up. My guess is that the first i3 tires were produced in 2013 or so, so if it is one of the early ones, it's getting closer to aging out. If it's a belt separation, it should be covered under warranty.