Foxsat apparently random channel lock

Humax Foxsat HDR: Every time I change channels to BBC2, it demands a password. But under the Menu setttings, it is not a locked channel, looks identical to all the others, and I can switch it from locked to unlocked with no trouble, but it demands the password, regardless of this setting.
Can anyone help, please - is there another way to set password protect? This happened out of the blue, never had the problem before, never ever used this function.