It's like comparing two person A and B of similar intelligence where A is smarter and B is a genius at signing, but signing was not on the test so person A won.
The rest is just the general reality I am sure you are familiar with:
- https://en.wikipedia.org/wiki/Catastrophic_interference
- https://en.wikipedia.org/wiki/Fine-tuning_(deep_learning)
- https://en.wikipedia.org/wiki/Entropy_(information_theory)