particle order problem

Hello! I use ovito.io in python, and change it into ase format by ovito.io.ase.ovito_to_ase but the order of atoms changes in different frames for example, in the first frame, it is ["Si", "Si", "O", "O", "O", "O",] then in the next frame, it becomes ["Si", "O", "Si", "O", "O", "O",]

if I use ase.io, the order of atoms is right. But ase.io is slower than ovito.io. If this problem could be fixed, it will be much better.

Thank you!