When previewing specific Roblox gears in 3D mode, the transparency of some parts of the gear is not displayed as intended. This issue affects the visual quality and accuracy of the preview.
Reproduction Steps
Open any web browser and navigate to Roblox.
Visit the asset page for one of the following gears:
The method to make it transparent in some accesories ,when modeling the UGC and Gears (etc) they added an surface appareance to the model with AlphaMode = Transparency withing the trasparent texture for the glass
But as your Slateskin Potion example ,is bugged because the viewport of the web due to being outdated while the web UI is being updated over the years, the viewport they cannot render AlphaMode ,Normal ,Roughness and Metalness making the gear loses his transparency
Poor viewport
They need to improve…
By allowing support of PBR
Thank for the bug reports JuanGamerPlayz_RBLX since Peru
Most Roblox-created catalog items don’t use SurfaceAppearance for transparency (including at least one of the linked accessories in the OP) since it wasn’t supported at the time of most (or even all, not sure) of their creation. Plus, even if it did exist at that time, it wouldn’t work in R6, unfortunately. The website is perfectly capable of rendering transparent accessories via the Transparency property, as seen here; the website just doesn’t render these gear as such.