When importing meshes in Roblox Studio using the Import 3D window, if you press Stop Import during the process and then press Import again, the system duplicates the number of tris for that mesh. If you continue clicking Stop Import and then Import, the tri count for each mesh will keep multiplying.
Image of the Import Queue window where this error occurs:
This makes the mesh appear to have significantly more geometry than intended, which can negatively impact performance, prevent creators from meeting tri limits (e.g. for UGC), and cause confusion.
This is a critical issue because Studio is currently experiencing problems importing meshes, often requiring creators to rename their files or (as shown in this report) stop the import and retry, since the process often times gets stuck.