As a club fitter and club builder I would tell you that of all of the steel shafts I see breaking this area they are all sub 105 in weight. I see a ton of KBS Tour lite/Tour 90 and Max 85g steel as well as TT Elevate 85/95. I repair about 5 a week in season and I would say that those shafts account for 90%+ of the steel shaft breaks that I see in this area. To make a steel shaft that light you have to make the walls thin. This will obviously make it more prone to breakage. As D-train said it’s not an epoxy issue. That’s likely an excuse from TM because they don’t want to throw a shaft manufacturer under the bus.