HI Team,

On entity main form Owner Lookup type field was placed on summary/general section. The same form was referred/used for bulk edit through advanced find and Owner field can't be searchable to edit. 

But working expected when field placed in Header section on form. Is there a reason behind it ? If so, Can you please suggest me if any explanation given ?! 

I referred in the below link, but no luck?! Help is much appreciated! Thank You!

Types of fields and field data types | Microsoft Docs