Here is everything I've done that may have affected this (DARK BROTHERHOOD SPOILERS):
Sided with the Stormcloaks (Dengeir is Jarl)
Killed Helvard for the Dark Brotherhood (READ: I've read that this automatically causes a problem, but from what I can tell, it looks like it's only if Siddgeir is Jarl?)
After Dengeir became Jarl, I was able to do one quest for Tekla - slay the giant at Secunda's Kiss - but that's it
Anyone know what the problem is? UESP says that sometimes the dialogue option will not appear, but what causes this? And is it fixable?