Using the API it is possible to add any type of data to a Field even if this field is a Boolean or a List.
There should be some kind of validation to make sure we give the proper type of data for a field
Metadata Update from @pingou: - Issue tagged with: bug
Metadata Update from @wombelix: - Issue set to the milestone: 5.13
Metadata Update from @wombelix: - Issue set to the milestone: 6.x (was: 5.13)