Character sheet health data corrupted when sheet closed

Issue report

Description of the issue

When you close a character sheet, the health data is corrupted by an additional save and the health "dot" statuses are all set to null

Expected behavior / Proposed solution

Saved character sheet data should retain its values

Reference

Steps to reproduce the issue

1. Create a new character, don't change anything and leave it open
2. Look at the data for it saved in actors.db, the health data looks like this: https://pastebin.com/f6CbqvLb
3. Go back into Foundry and close the character sheet. This saves a new row in the actors.db, but now all the health dot statuses have been set to null: https://pastebin.com/tSC0Vn5e

Environment

• Browser with the issue: Chrome and Firefox
• Foundry VTT version: v0.8.9 and v9
• CONAN 2D20 version: 1.2.0