What are you attempting to achieve? Union my track together to prevent bumps which can destabilize the cars
What is the issue? The track size gets smaller when I union it video
What solutions have you tried so far? I have tried disabling CSGv2 as I read through the devforum and found this was an issue however it did not work.
Check if one of the x, y, z for the union’s size has 2048 (the limit of size for parts). That may be the problem, as it will downsize it to comply if it goes above the size limit.