And my (hopefully) last post about this...
Been playing around with things, and learned a few new pieces of info about when this bug appears.....
Seems that if I exit the game and then load a save again, things work normally until one of the following things occurs (not an exhaustive list, probably, but only what I have seen in my game and repeated a couple times to make sure it is a consistent bug when these events occur)....
1) Open the diary (discussed before)
2) Use a textbook (to get one free learning point)
3) Use any rune to get a new spell in my arsenal (well, at least the three runes I acquired while testing these things...)
But (again), at least the couple times I've tried it, seems that exiting completely and then restarting nehrim resets things to 'normal' until one of the above occurs again...
Thanks again.