Something like this will happen with all soles sooner or later. Usually beginning 5 years after having been manufactured.
The glue and the softener in rubber and PU-foam detoriate. UV-rays and fumes may hasten this.
It may happen on tour or with boots stored in the basement.
We have lots of customers coming into the shop for a re-sole. The luckier ones didnt experience this while out and in the middle of a tour several days long.
With a quality brand, and a construction based on an insole around which the upper is formed, a re-sole is nearly always an option.