Carlisle usually has about as good of products as anyone else.
A leak on the side of the tire is usually suspect of a tire cut and will pinch a tube by tire flex until it fails no matter the brand. Examine it carefully inside because it may need a Boot.
They crack & fail for two reasons
Firstly they never get hot enough & flex enough when hot to cause the plasticisers in the rummer to migrate to the surface t replace those that the UV has degraded
Secondly no one ( other than me ) bothers to put tyre dressing on the sidewalls to counter cat the effects of the UV rays
This is naturally worse on mowers tat are stored where sunlight can fall on the sides of they tyres 365 days a year
If you cut the printing off the tyre so the sidewalls are a uniform thickness then you won't get the cracking and leaks that originate around the lettering because it is thicker and does not flex as much as the actual sidewalls so acts as a stress concentrator.
This effect is substantially worse on 2 ply tyres than on 4 ply tyres .