Anycubic Chiron does not print correctly
It is impossible to give a definitive answer without photographic evidence, since your description of the problem does not give enough information. The most common causes of "circular objects not printing correctly" are loose belts and loose grub screws on the belt drive pulleys.

However, you should note that the printer's firmware will not allow the print head to be moved outside the defined maximum printing area under software (g-code) control. This will cause large objects to be truncated if they extend outside of the defined maximum printing area, and I suspect that this is what is happening.