Restkit: Native iOS Swift app crash in Xcode 12.5

Question

When MKMapperOperation tries to map attribute value it throws an exception :

Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<RestKitExample.xx0x600002d463e0> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key token.'

It was working fine with code 11.xx.The crash started when I updated to Xcode 12.

I have tried following but no luck:

RestKit RKObjectMapping Swift Optional

I have created the following issue on the Restkit git repo as well. But yet no luck from there:

https://github.com/RestKit/RestKit/issues/2562