Customer field hidden in Subscription card

I just updated our ERPNext from 10.0.x to 11.1.13.
Now all our subscriptions are gone (that’s not to worry cause I see that the whole principle has been changed).
The weird part is that I can no longer set the Customer field for a new subscription.
When I try to change it, it says that the Customer is mandatory, but I cannot see it. It is hidden though. When I open up the page content, I see the field, but it’s totally disabled and hidden.

Any solutions to this problem?

Ps. I did have a custom field “is_frozen” added since 10.0.x. Maybe that has something to do with it?

This is still an issue. Can someone elaborate?