It is probably about this decoding chip that is installed in the battery:
"The battery is equipped with a fully-fledged decoding chip and supports various cameras perfectly without causing pop-up windows."
This is why incompatibility is pointed out. However, this does not mean that you cannot use these batteries in an FX30. It is otherwise a normal 3rd party NP-FZ100 battery. The camera will simply display the message that it is not an original battery.
For me with Sony A7IV so far without problems, but only as a backup in case of emergency (e.g. no experience in extreme use in cold weather or for longevity)