Oh it's just GDB terminology.

Career change are dogs who for various reasons are not becoming guides. This puppy had an operation, but is now fine. Career change covers a wide variety of things, and they're pretty restrictive on which dogs are actually selected as guides. Some 30+% of all their puppies career change out.

Fostering is a temporary housing for a dog waiting for adoption - to get the puppy out of the kennel and into a real home while it is waiting for placement. The foster will continue to happily foster him til he is placed.

These are not negative things about the pup.