In Issues, in response details, "First Response Time" is not showing

I tried this thing on v15.15.0 and v14.27.1 (version-14),

What I want to get is the time between the issue ticket got created and the first response, and it seems that this is done already, in the “Response Details” section, and it goes farther to calculate the average time of response

For me both versions, does not show “First Response Time” and “Average First Response Time” and the “First Responded On” can be manually entered, or auto assigned if the SLA changed, either to pause or resolved.

It is in read-only.

Please check the code:

if i keep the fields as read only, they does not show in the form

but if I removed the read only it shows in the form