Originally Posted by buggss
Same problem, I understand it's related to you killing his servant guy, Val-something earlier in the Dark Brotherhood questlines meaning Siddgeri in Falkreath doesn't like you meaning he never unlocks the land-purchase option.
It's actually correct. Unless you have a save data before you kill Helvard in the Dark Brotherhood, there's no chance you can get the land (at least from the 3 hours of trying to test all possibilities). It's an old bug which from the looks of it it was never looked up/never bothered to be fixed. Only have 2-3 miscellaneous quests not related to anything "Thane" related and I'm sure it's the whole Helvard thing since you still get the quests from Nenya (which isn't "glitched") but rather the Jarl itself. :/
Hopefully of course it doesn't glitch with everyone.