Values sent as mutation are set to null after the initial time

[IzumiSy]

Describe the bug

After sending mutation at the initial time, the values that is being sent are unexpectedly set to null.

Steps to reproduce

1. Adding a form
2. Sending values through the form (and sure it works)
3. Sending values again without any modification.
4. All values sent are null.

Expected behavior

The form fields should be reset after sending mutations successfully.

Environment

N/A

Additional context