### Bug summary When STRU contains below info: <img width="1210" height="418" alt="Image" src="https://github.com/user-attachments/assets/c3d21f00-a397-4efa-b59d-ecdfc9bd9323" /> ### dpdata Version latest ### Input Files, Running Commands, Error Log, etc. Error: <img width="1878" height="494" alt="Image" src="https://github.com/user-attachments/assets/419df540-e7bd-46c5-b317-c2f5ed41cd26" /> ### Steps to Reproduce By using commands below to convert to lammps format, addition info will be added, but lammps will not recognise this: ```python import dpdata stru = dpdata.System("dpgen2/lcao_effi/assets/start_stru/SiC_3C_3x3x3", fmt="abacus/stru") lmp = stru.to(fmt='lammps/lmp', file_name="SiC_3C_3x3x3.lmp") ``` ### Further Information, Files, and Links _No response_