It has been possible for some time to have an single autocomplete-enable field that supports multiple comma-separated items. The most common use is in entity reference fields. Cardinality for these fields is configurable, making it possible to limit the number of items.
Prior to this change, the configured cardinality was not enforced clientside. This meant that users could potentially add more items than allowed by the input, but when the form was submitted, the excess items would be silently stripped away and not saved. This has been addressed.
With this change, autocomplete inputs that have reached the configured cardinality limit, will not provide suggestions when the limit is reached. This prevents the addition of items in the form that will not actually be included in the saved data. Functionality has not changed in any way, but the forms now reflect that functionality accurately.
