Obeject Repo - Web Service Request - HTTP Header - value reset or defaulted

I am using Katalon to verify Kafka message and found the ‘value’ isn’t available:

i can add them manually, but when i copy the Request, it reset to standard value ‘application/json’.
sometimes the value reset when i navigate to HTTP Header then back to body , or sometimes when i ass new
HTTP Header, the uncommon value as example got reset.

please take a look.