Problem setting batchSize for REST Sink in ADF Dataflow

In ADF Dataflow with the Sink of type "REST" there are problems saving batchSize value.

If I run (Debug) the pipeline using this dataflow immediately after I put the batchSize value, then it works.
But if I refresh the page or try to run pipeline later after some other changes have been made, then I can see that batchSize field is empty (on UA) and I get an error during the runtime showing me that the data wasn't batched before sending to REST endpoint.

Also on UI the Batch Size input box expects the value to be of **String** datatype, but then when I run the pipeline, I get the error that batchSize is expected to be an integer.

If I put a numeric value for batchSize (e.g. 100), then field validation fails and value is swept out after page reshesh.