Unable to Remove and Save entity queue items

Problem/Motivation

In Entity Queue module when we decrease amount of restrict queue for existing amount items, then we are unable to Remove, Reverse, Shuffle, Clear and Save it.
For example, I created a queue where I limited the queue from 1 to 4, then I add items and save it. Then I decrease the queue from 1 to 3. When I back to the created queue and try to edit the items, then is not possible remove, reverse, shuffle, clear and save.
When press Save button then message is displayed: This queue can not hold more than 3 items.
Items: this field cannot hold more than 3 values

Steps to reproduce

1. install Entityqueue 8.x-1.2
2. create new queue: Structure->Entityqueue ->Add entity queue
3. configure entity queue: mark checkbox Simple queue and in Queue settings tab add restrict queue from 1 to 4 and save it
4. navigate to entity queue and click on Edit items created queue: Structure->Entityqueue
5. add 4 items and Save
6. change Restrict queue maximum for 3: Structure->Entityqueue->NameCreatedQueue and Save
7. back to created queue and Edit items: Structure->Entityqueue and click Edit items button on right created queue
8. button: Remove, Reverse, Shuffle, Clear, not work and when try to Save then message is:

This queue can not hold more than 3 items.
Items: this field cannot hold more than 3 values.

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes