Bulk import throws exception when certain custom field attributes are defined

[atownson]

Deployment Type

NetBox Cloud

NetBox Version

v4.2.6

Python Version

3.12

Steps to Reproduce

1. Add a custom field named "my_cf_field" to the model Site (or any other model) of Type "Multiple object" - set as not required, enter [1,2] as the Default value, and set Related object type to Region (or any other model).
2. Ensure that at least 2 Regions exist (with IDs of 1 and 2) - to populate the default values
3. Attempt to bulk import a Site with the following payload:

name,slug,status
My Site,my-site,active

Expected Behavior

The site is created and the custom field "my_cf_field" is set to the default of Regions with IDs 1 and 2.

Observed Behavior

An exception is thrown: 'list' object has no attribute 'split'
The exception location is /opt/netbox/netbox/utilities/forms/fields/csv.py, line 82, in clean