On Retail, using version 2.3.0 of TTV, a LUA error is happening when trying to unlearn any talent on the Outlaw Tree that breaks things further down the tree.

1x ...eTweaks/libs/LibTalentTree-1.0-14/LibTalentTree-1.0.lua:108: stack overflow
[string "@TalentTreeTweaks/libs/LibTalentTree-1.0-14/LibTalentTree-1.0.lua"]:108: in function <...eTweaks/libs/LibTalentTree-1.0/LibTalentTree-1.0.lua:107>
[string "@TalentTreeTweaks/libs/LibTalentTree-1.0-14/LibTalentTree-1.0.lua"]:113: in function <...eTweaks/libs/LibTalentTree-1.0/LibTalentTree-1.0.lua:107>
[string "@TalentTreeTweaks/libs/LibTalentTree-1.0-14/LibTalentTree-1.0.lua"]:316: in function GetLibNodeInfo' [string "@TalentTreeViewer/TalentViewerUIMixin.lua"]:287: in function callback'
[string "@SharedXML/TableUtil.lua"]:414: in function <SharedXML/TableUtil.lua:410>
[string "=(tail call)"]: ?
[string "@TalentTreeViewer/TalentViewerUIMixin.lua"]:628: in function ProcessGateMandatedRefunds' [string "@TalentTreeViewer/TalentViewerUIMixin.lua"]:590: in function UpdateTreeCurrencyInfo'
[string "@TalentTreeViewer/TalentViewerUIMixin.lua"]:483: in function AfterRankChange' [string "@TalentTreeViewer/TalentViewerUIMixin.lua"]:462: in function SetSelection'
[string "@TalentTreeViewer/TalentViewerUIMixin.lua"]:631: in function ProcessGateMandatedRefunds' [string "@TalentTreeViewer/TalentViewerUIMixin.lua"]:590: in function UpdateTreeCurrencyInfo'
...
[string "@TalentTreeViewer/TalentViewerUIMixin.lua"]:631: in function ProcessGateMandatedRefunds' [string "@TalentTreeViewer/TalentViewerUIMixin.lua"]:590: in function UpdateTreeCurrencyInfo'
[string "@TalentTreeViewer/TalentViewerUIMixin.lua"]:483: in function AfterRankChange' [string "@TalentTreeViewer/TalentViewerUIMixin.lua"]:462: in function SetSelection'
[string "@TalentTreeViewer/TalentViewerUIMixin.lua"]:631: in function ProcessGateMandatedRefunds' [string "@TalentTreeViewer/TalentViewerUIMixin.lua"]:590: in function UpdateTreeCurrencyInfo'
[string "@TalentTreeViewer/TalentViewerUIMixin.lua"]:483: in function AfterRankChange' [string "@TalentTreeViewer/TalentViewerUIMixin.lua"]:472: in function RefundRank'
[string "@TalentTreeViewer/TalentViewerUIMixin.lua"]:158: in function `RefundRank'
[string "@Blizzard_SharedTalentUI/Blizzard_SharedTalentButtonTemplates.lua"]:1119: in function <...redTalentUI/Blizzard_SharedTalentButtonTemplates.lua:1105>

Locals:
original = "visibleEdges"
(*temporary) = defined =[C]:-1
(*temporary) = "visibleEdges"
(*temporary) = "stack overflow"
deepCopy = defined @TalentTreeTweaks/libs/LibTalentTree-1.0/LibTalentTree-1.0.lua:107

interesting bug, fixed in next version