Unable to Publish a Model (attempt to index nil with 'ClearAllChildren')

Basic Description

We have a model that we use to store vehicles & customizables for our game Drive World. I am unable to publish this model, as when I attempt to do so, the publishing dialog box closes, and I receive an error in my output. I am the only one on my team who has this issue, and I am also a UGC creator, so my model publishing dialog box differs slightly from theirs. We suspect this might be part of why this issue is me specific.

Issue Walkthrough

(repro model included in private message)

When I go to publish this model (right click → save to roblox), I am presented with this dialog box:

if I select Model, the window immediately closes, and I am given this error in the output:

studio output.txt (10.7 KB)

As a result, I am not able to publish the model, and I cannot bring the previous dialog box up again until after I restart studio.

System Information:
Windows 11
AMD Ryzen 5 5600G
NVIDIA RTX 3060
16 GB of RAM

Beta Features:
UGC Bodies & Heads
Upgrade Shorelines

A private message is associated with this bug report

I’ve just realized right after publishing this that this is probably a duplicate of @berezaa’s report here:

I don’t know the etiquette for handling duplicate reports so please keep that in mind and feel free to close this thread if necessary.

I’ve made a reply on that thread that should apply to you as well.