[Bug]: Customized new tab page background does not appear on startup

[Leilei332]

Pre-Submission Checklist

• [x] I have checked the existing/closed issues to ensure this issue has not already been reported.
• [x] I am using the latest supported version of the browser.
• [x] I have tried disabling all browser extensions/add-ons to rule out interference from these.
• [x] I have tried clearing the browser cache and cookies.
• [x] I have checked with a new profile and the issue still occurs.
• [x] I have provided detailed step-by-step instructions on how to reproduce the issue.
• [x] I have included relevant screenshots or console outputs.
• [x] I have checked that this problem is not occurring in the latest version of Firefox ESR.
• [x] This issue is specific to this browser and does not occur in other browsers.

Bug Summary

When setting a customized image for a new tab page, and the option "Open previously opened tabs and windows" is unchecked, the background of the new tab page won't appear.

Reproduction Steps

1. Create a new profile
2. Go to about:preferences. Uncheck "Open previously opened tabs and windows"
3. Go to about:preferences#home. Change "Floorp homepage background image" to "Customized image" (and manually select one image).
4. Repeat restarting Floorp for several times, the background will become black

Expected Behavior

The background image is displayed correctly:

Actual Behavior

The background image is displayed correctly when creating a new tab, but the background image is black on startup:

Screenshots

Browser Version

11.23.0

Operating System

Windows 10 22H2

Additional Context

No response