Datetime Tag with `only="time"` Parameter Fails to Display Selected Value

#### **Description**
When using the `datetime` tag and setting the `only="time"` param, the selected time value fails to display correctly. Symptoms include:
- This value is updated only at the first time of the two selections/inputs, the subsequent changes will make the result empty;
- The exported dataset also lacks this field's value.

In addition, the following error appears in the browser console whenever the value is not properly displayed:
```
Error: [mobx-state-tree] You are trying to read or write to an object that is no longer part of a state tree.
(Object type: 'ClassificationArea', Path upon death: '/annotationStore/annotations/0/trackedState/areas/5hXc7ZWBTH', Subpath: '', Action: '/annotationStore/annotations/0/trackedState/areas/5hXc7ZWBTH.updateAppearenceFromState()').
Either detach nodes first, or don't use objects after removing / replacing them in the tree.
```

#### **Steps to Reproduce**
1. Add two `datetime` tags to config;
2. Add `only="time"` param;
3. Label a task and attempt to select or manually enter a time;
4. Observe whether the data exports correctly;
5. Open the browser console and check for related errors.

#### **Expected Behavior**
- Each change should trigger an update in both UI and model state;
- The exported result set needs to have correct datetime data
- No MobX-State-Tree warnings should appear in the console.

#### **Actual Behavior Screenshot**