Some parts not being rendered (sometimes) after SubtractAsync

[rogeriodec_games]

I’m creating walls via Server Script, and making holes for windows, using SubtractAsync.
For some reason, sometimes, when I run the game, some resulting walls are not being rendered, although its properties are apparently ok, as detailed here:

Sometimes a material is not being shown in part

I don’t know why, but sometimes, when I start the game, although a part is correctly created, it’s appearing as completely transparent, like this wall: [image] However, its properties are ok: [image] If I stop the game and run it again, the part is correctly shown: [image] The Output Window shows no errors… Is there a way to avoid this?

As I said, sometimes the wall appears correctly, sometimes not.
And there is no error on the Output Window.
I sent the project and logs via DM: https://devforum.roblox.com/t/log-and-project-about-rendering-problems/819506

How to avoid this?

Repro

1. Save the game to Roblox (I use DataStore2)
2. Run the game
3. Maybe, sometimes one or another wall is not rendered.

[PeZsmistic]

This is most likely a duplicate:

Unions disappearing / turning invisible after creation

Working on a game for a client that included 24 fairly simple unions, upon publishing the game all unions have now disappeared, they still show in explorer however they are invisible. Attempting to de-union them causes the union to delete itself from the workspace as if it never existed. No attempts to recover the data for these unions have yet been successful. I can’t paste a repro here as it is a private client however I would be more than happy to privately DM one to an admin/engineer on re…