Lookup search template behavior for standard vs custom relationship fields

Hi, Sunny,
I tried to reproduce your issue and wasn’t able to reproduce any kind of problem. When you say “the data for standard account field is not returned”, are you saying that, when typing a value into the autocomplete field, the external Id field values do not show in the dropdown of lookup results (as in, an empty dropdown)? Or does no dropdown display at all? I used your xml and made a couple of changes:

  1. Changed the search template and display template to use our own custom external id field.
  2. Changed the lookup filter on the AccountId field to use a record type DeveloperName from our own org.
    Here is what I got when trying to search on the external Id field:

I would check the permissions on your external Id field. Is it possible that your users aren’t given permission to view the external Id field?
Emily