Record doesn't support null values

Very frequently NetSuite records contain null values due to missing data(for instance), we need to support isNullable in our component.
The issue occurs in Studio, when run designed job. The exact place of issue happens here:
1. Runtime Converters converts to JsonObject type.
2. e.g. String value is null, we try to add it here
3. Johnzon Builder tries to add null value
4. But happens NPE here

By the contract defined in Schema.Entry we can specify if it's nullable or not.

In my current implementation I specify this field when set up runtime schema