Ref Rows not showing the actual value in child table

[syed1524]

The ref values in child table are not reflecting correctly and it shows a random number/id instead of actual value, I have vehicle number in parent table  which i want to link with child table.
Example :vehicle number- IN-0099, but child table shows me vehicle number as 92c69012, attaching screenshot below.

Can anyone please help to solve this?

Parent table response:

Child table response: