Help with unassigned shards / CircuitBreakingException / Values less than -1 bytes are not supported

[DevFullStack (Ricardo)]

I may have found a breaking change in v.7.4 on testing the upgrade from 7.1.0 to 7.10.1:
Ignore_malformed fires mapper_parsing_exception for keyword type on 7.10.1 (it worked on 7.1.0)