Fields with behaviours become inline-editable if you edit another field inline first

To reproduce:

• Set up a behaviour that sets a field to read-only.
• Go to an applicable issue's view screen and try to edit the field inline.
  • The edit screen will open instead and the field will be read-only: this is as expected.
• Close the screen and click on a different field to edit it inline.
• Hit enter or click the tick mark to complete the edit (you don't actually have to chance the field's value).
• Try to edit the original field inline again.

Expected: The edit screen opens again and the field is read-only.

Actual: The field is editable inline.

I've not been able to investigate much beyond the above, but it looks like the act of confirming the edit of the other field causes some parts of the screen to get refreshed, possibly wiping away any hooks we have set up to prevent inline editing. Note that you have to confirm the edit, even if you don't make any changes: clicking the cross mark will not trigger the bug.