[5.x]: Intermittent "Server error occurred" when setting focal point after editing entry with editorial modules — plus blank entries list on save

What happened?

Craft CMS: Pro 5.9.22
PHP: 8.4.11
OS: Linux 6.17.0-1013-aws
Database: MySQL 8.0.44
Image driver: GD 8.4.11
Yii: 2.0.54 | Twig: v3.21.1 | Guzzle: 7.10.0
What happened:
While editing a General Page entry with multiple editorial modules, attempting to set a focal point on an image intermittently throws a "Server error occurred" popup and the focal point modal goes blank. Additionally, the entries list shows blank rows after saving, requiring a browser refresh to fix.
Steps to reproduce (intermittent):

Open a General Page entry (e.g. "Our Valued Staff")
Add several editorial modules to the page
Attempt to add/edit a focal point on an image field
Intermittently — "Server error occurred" toast appears, focal point modal goes blank
After saving and returning to Entries > General Pages — some entries appear completely blank until page is manually refreshed

Expected behaviour:
Focal point modal opens reliably with image visible. Entries list shows correct data after save without requiring a refresh.
Workaround:

Focal point error: click browser Back, re-enter the page and try again
Blank entries: manually refresh the browser

Frequency: Intermittent — not reproducible every time. More likely after leaving and returning to the asset modal within the same editing session.
Suggested investigation:
Check storage/logs/web.log and server error logs at the time of occurrence — the actual error will be recorded there even when the frontend only shows "Server error occurred."

Craft CMS version

5.9.22

PHP version

8.4.11

Operating system and version

Linux 6.17.0-1013-aws

Database type and version

MySQL 8.0.44

Image driver and version

GD 8.4.11

Installed plugins and versions

Reproduce the focal-point and save workflow for a General Page with several editorial modules, then inspect storage/logs/web.log and the server error logs at the time of failure. Use the recorded error to narrow the affected subsystem; done means the focal-point modal remains usable and the Entries list shows complete data after saving without a manual refresh.