Time to refresh this thread with new information. I just noticed that out of completely weird reasons it ALL seems to be connected to profiles.
As described above, the annoying alarm clock beeping only occurs in my old, veteran profile ... however - that profile suddenly has correctly working reward weapons. I don't know how THAT happened ... on my new profile however there is no alarm clock bug - yet sadly the reward weapons are not working correctly (though I just noticed that they DO work in a way- it's just that they are not shown visually in any way (no change of colour of the shots - and no 'reward "gun"' text when you switch the weapons). Weird ... It seems to be configured identically ... does anyone have an idea on how to unravel this mystery?
Mmmh ... correction: it seems that I just had a lucky phase with my regular blaster rifle - and that the award weapons on my second profile don't work at all.
Still - the fact remains that they work just fine on my old, sound bugged, profile. How can that be the case?