Validation error popup incorrectly appears when inline editing

[kinglozzer]

Module version(s) affected

5.3.0

Description

After the first AJAX save has happened, subsequent ones trigger a validation error popup when there are no validation issues. Clicking to save a second time (basically ignoring the error popup and trying again) works as expected.

In the video below, I add two content blocks but the same thing happens when only one is added.

Note: I have not yet validated that this issue occurs on a blank install, though I’m fairly sure it will as I removed any extensions from BaseElement/ElementContent before recording the video, I just wanted to write this up while I have the affected project open to demonstrate.

test.mp4

How to reproduce

• Add a content block, save and publish
• Click to edit, make a change
• Click save and publish, a validation error popup appears
• Click save and publish again, the content is saved as expected

Possible Solution

No response

Additional Context

No response

Validations

• Check that there isn't already an issue that reports the same bug
• Double check that your reproduction steps work in a fresh installation of silverstripe/installer (with any code examples you've provided)