Placeholder_Task disappear

I’m having an issue where the placeholder task is disappearing/not being added to the bottom of the gantt after a second task is added via a custom lightbox. This issue only occurs when the parent is initially childless. Any suggestions for a potential fix or workaround would be greatly appreciated?

Hello Justin,
I couldn’t reproduce the issue in the following snippet:
https://snippet.dhtmlx.com/pk9k6gdu

Probably, the issue is related to the Gantt configuration, but it is hard to suggest what might be wrong as I don’t see your code.
Please add your configuration to the following snippet and make sure that the issue is reproduced there:

Then, click on the Save button and send me the link.
Or send me a ready demo with all the necessary JavaScript and CSS files so that I can reproduce the issue locally.