I hardly ever had this problem with Thaumcraft 4 proper, just with TT. Then again, TT is by far (my) largest TC4 Add-On mod, so of course I'd be more likely to see it in TT than any other TC4 Add-On mod.
Azanor must know how to use (work around) his node-selection algorithm well enough to mostly avoid it in TC4 proper.[DOUBLEPOST=1387208278][/DOUBLEPOST]
That indicates that you have a bonus research point, so when you run out of that aspect you get the one free point.
Yes, and you should use that to your full advantage. You only get 1 and only 1 bonus point if a primal aspect is at zero.
Always try to keep the following primals at zero(0):
...by combining into these "must-have" 2nd-tier aspects:
Motus = Aer + Ordo
Victus = Aqua + Terra
Vacuos = Aer + Perditio
Potentia = Ordo + Ignis