Steps to reproduce:

1. Create a new calculated item prototype from a discovery rule that uses db.odbc.discover()

1. Create an item prototype with the following parameters:
   Name: {#LLD_MACRO} foo
   Type: Calculated
   Key: foo{#LLD_MACRO}
   Formula: {#LLD_MACRO}
   Type: Numeric unsigned

1. Create fails on 'Incorrect value for field "params": cannot be empty

Result:
See screenshot