I have problem with my Fingerprint unlock, when i set fingerprint, it works well for a couple of hours, then it seems as BV7000PRO forgot my fingerprints.......? When i set new FIngerprint, it is same, works for couple of hours.

I have Android 6, Build number BV7000_PRO_Blackview_20170411

I will test If I have the same problem.

It is working for me. Did you install or activate some kind of battery saver?
If not maybe you should try a factory reset.