Mautic: Custom field - Multiple choice - Not populated by form

[mundo03]

What type of report is this:

| Q | A
| ---| ---
| Bug report? | yes

Description:

Multiple choice filed data reaches the form but does not reach the contact.

If a bug:

| Q | A
| --- | ---
| Mautic version | 2.8.1
| PHP version | 5.6.30

Steps to reproduce:

1. Create custom field and set it as multiple choice
2. Create a form that sends data to that custom field.

actual Behavior

Form has the data, contact does not.

expected behavior

Contact should have the data on the given custom field

Log errors:

Nothing in the logs

[npracht]

Hi, we're currently working on it with @MaxWebmecanik

[npracht]

+duplicate https://github.com/mautic/mautic/issues/3741