The SDK is crashing. It's likely crashing because the service changed, but it's causing actual crashes on iOS and Android devices which rely on the SDK.
And even worse it doesn't crash in realtime. It crashes parsing locally cached data caused by a bad update, meaning this possibly can't be quickly fixed merely by fixing the API.
Imagine writing a test for that. Just to replicate it repeatedly. Would they be able to use a phone emulator and point it to the old api to cache data, and then go to the new api to replicate the failure?
That actually doesn't sound that hard, it's very similar to writing e2e tests over Selenium (except in this case instead of talking to chrome you're talking to the android emulator).