Error when trying to enable adjustments

I just repeated the steps and everything is working fine. Can you provide more details please?

It seems that the adjustment field doesn't have a formatter. I think we need to attach some default formatter for the adjustment field. Let's say some formatter that have price field because adjustment it's also a price.

You can try this patch, it should fix your problem. We just attach the default formatter for our adjustment field.

This is still active for me also. Composer.json attached what i used for test this.
Bug is appear when u move the Adjustments field from hidden to the visible region and hit the save button.

I don't really consider this a major bug as nothing happens if you simply don't drag the adjustments field to display it...
I don't think it makes sense to use the PriceDefaultFormatter either.

So that leaves us with 2 options:

1. We define a new formatter, but not sure what the formatter would do? Output a table? Just an HTML list of adjustment labels => values
2. Remove the following: ->setDisplayConfigurable('view', TRUE);

I think the second option is better for now, unless you really need to display the order item adjustments somewhere? I don't really see what would be the use case for that?

The attached patch is addressing the option #2.