Software error or defective fingerprint sensor?

I've just noticed something very strange on my Huawei Mate 20. I have the fingerprints of my thumb and forefinger registered in the device. If I now take one of the 3 other fingers and press it 3 times to the sensor, the device is unlocked after 3 short vibrating. Is the sensor defective or is there a software problem?

Can be both you can try a hard reset or a rollback on the hisuite. If the error still occurs then the device must be in the workshop