Your pro shop and Titleist customer service (listed on the bottom of the web page) are your best resources. These sites are only moderated by Titleist personnel for the benefit of end users and not as an avenue for customer support. They basically don’t post obscene/rage comments or offensive critique of other companies by name. The last part for legal liability.

Fairway and drivers are at the edge of limits for performance. Using multiple materials (carbon fiber crowns, metal faces, etc.) they are prone to failure. This happens with all the top performing brands. One of my partners has cracked 3 drivers from 2 other companies over the last 3 years with their top performing drivers. Once you are past the 1 year warranty period, any adjudication based on defective manufacturing becomes a gray area. Titleist may or may not want to look at a specific model. But worth checking to see if they will inspect it.

Titleist is concerned about breakage and face shallowing - their testing involves approving designs that can withstand a great deal of testing.

I have a TSI2 F 15* in my bag and have had no issues with it. Play three days a week and purchased mine when they were first released. You did not mention how long you have have had it. Titleist recommends taking it back to the Titleist account where you purchased it with you receipt, within the first year. The account would notify Titleist and get a return authorization for them to return it for inspection. Titleist has a one year warranty on all their equipment as stated below.

Limited One-Year Warranty Information
Although Titleist is committed to satisfying golfers with golf products of superior performance and quality, there is a chance a warranty claim may arise.

Acushnet Company warrants its Titleist products for a period of one year from the date of purchase against defects in materials or workmanship. Should your Titleist product fail to perform for either of the above reasons, we will at our option, repair it or replace it with an equivalent product at no charge. To obtain the benefits of this warranty, please contact your local golf shop to set up a Return Authorization. If you need assistance locating a shop in your area, please visit the Titleist Golf Shop Locator. Enclose the original receipt along with an explanation of the defect in writing. We ask that all parts of the product be returned to the repair department and that the product remain in original factory condition. Warranty claims presented without the original sales slip will be reviewed at our sole discretion. Acushnet Company reserves the right to inspect all warranty claims to determine the extent of warranty applications. All products returned for warranty claims become the property of Acushnet Company.

Acushnet Company will not be liable for any consequential or other damages arising from the use of this product or any delay in the performance of this warranty due to causes beyond the company’s control. Some states do not allow the exclusion or limitation of incidental or consequential damages, so the above exclusion may not apply to you. This warranty gives you specific legal rights, and you may also have other rights which vary from state to state.

You should start by taking the clubs to the retailer where you purchased them. Or if directly from Titleist then call customer service.

Titleist will not respond to this post but you are welcome to contact customer support and talk specifics with them and see what they say. Stock answer is that the one year warranty is in effect. Lighter, thinner faces on all brands have experienced the occasional problems as demand for clubs that go father are more susceptible to damage, especially from the small population of high swing speed hitters and those that use hard range balls or hit more off-center shots.

I bought a TSi2 18° and couldn't seem to hit so didn't use it for 18months, tried it again 4 weeks ago and was hitting it well, yesterday the face cracked. Obviously out of warranty but literally 4 games old. Not impressed. Have been using the 21° all that time and no problems though.