Well, maybe there's 3rd part and there's 3rd party batteries around then.
Other than the one-hour battery that came with it I have only ever used 3rd party batteris on my Sony FX1. both bought and recommended by a reputable dealer. I've never had a moments problem with any of them.
edit: And as your original question was for recommendation then. I got them here.
HDRFX7E - HVR-V1E - SONY HVRZ1E - SONY DSRPD170P - SONY PDWF330L who I know as "H Preston". I've had no issues with them - dealer or product.