Bug: When using the Brush tool, "incomplete brush" error occurs

[ferris001]

Describe the bug
When using the Brush tool in Label Studio v1.17.0, an error occurs during or after drawing. Sometimes the brush region becomes unusable, and a browser console error is thrown related to a BrushRegionModel being accessed after removal from the state tree.

To Reproduce
Steps to reproduce the behavior:

1. Open a labeling task with the Brush tool.
2. Press the left mouse button to begin drawing a brush region.
3. Release the left mouse button, browser console shows MobX-State-Tree errors about accessing a disposed BrushRegionModel.
4. Press the left mouse button outside the region to drawing new brush region, The UI throws an "incomplete brush" error until release the left mouse button.

Expected behavior
Release the left mouse button to end the current brush region, press the left mouse button again to start a new brush region.

Screenshots

Environment (please complete the following information):

• OS: MacOS 15.4
• Browser: Chrome
• Label Studio Version v1.17.0