[5.x] Adding more than 2 elements to a Neo block throws an error: 'There was a problem getting the previous element.'

[AleksanderKampus1]

Bug Description

While working on an entry that is already saved once, I can't add more than 1 block to the parent Neo block. When I try to do it I get Request failed with status code 500. And looking at the logs I see this error 'There was a problem getting the previous element.' Here is the stack trace if it helps:

#0 /app/vendor/spicyweb/craft-neo/src/controllers/Input.php(146): craft\services\Structures->moveAfter(341200, Object(benf\neo\elements\Block), 17071011)
#1 [internal function]: benf\neo\controllers\Input->actionRenderBlocks()
#2 /app/vendor/yiisoft/yii2/base/InlineAction.php(57): call_user_func_array(Array, Array)
#3 /app/vendor/yiisoft/yii2/base/Controller.php(178): yii\base\InlineAction->runWithParams(Array)
#4 /app/vendor/yiisoft/yii2/base/Module.php(552): yii\base\Controller->runAction('render-blocks', Array)
#5 /app/vendor/craftcms/cms/src/web/Application.php(350): yii\base\Module->runAction('neo/input/rende...', Array)
#6 /app/vendor/craftcms/cms/src/web/Application.php(649): craft\web\Application->runAction('neo/input/rende...', Array)
#7 /app/vendor/craftcms/cms/src/web/Application.php(312): craft\web\Application->_processActionRequest(Object(craft\web\Request))
#8 /app/vendor/yiisoft/yii2/base/Application.php(384): craft\web\Application->handleRequest(Object(craft\web\Request))
#9 /app/web/index.php(83): yii\base\Application->run()
#10 {main}

Steps to reproduce

1. Make a new entry
2. Add some blocks to it (try adding multiple inside one block)
3. Everything should work fine
4. Now save the entry
5. Try to adding a new block and inside it multiple new ones
6. You should get Request failed with status code 500

Auto save drafts is set to false if that changes anything

Added also a video where you can see a totally new entry where I can add multiple Neo blocks. However when I save and try to do it again then I get 500.

Screen.Recording.Jan.7.2025.2.mp4

Expected behaviour

I can add multiple blocks inside a Neo block

Neo version

5.2.21

Craft CMS version

5.5.8

What is the affected Neo field's propagation method?

No response

Does this issue involve templating, and if so, is eager-loading used?

This is not a templating issue

[AleksanderKampus1]

It works in 5.2.13

[ttempleton]

Thanks for reporting that - fixed for the next release.