We have seen a customer that ends up with the same field having two different types in a single shard.

The two types are in different TSM files within the same shard, which causes a panic when those TSM files are being compacted together.

It s unlikely we will be able to fix the panic; our goal would be to prevent the gap in type checking from allowing the two types in one shard.

Many more details from @btasker in a closed Engineering Assistance Request in a private repository.