Version: TalentTreeTweaks-v1.9.7
All AddOns disabled

If there is an export string in chat, I can't post it in chat with shift + left click as described by the tooltip.

ClickableExportStringsInChat.lua line 145 - 154:

if IsShiftKeyDown() then
    if "LeftButton" == button and self.talentBuildLinksSupported then
        local fixedLink = GetFixedLink(text:gsub('garrmission:TalentTreeTweaks', 'talentbuild'));
        ChatEdit_InsertLink(fixedLink);
        return;
    else
        Util:CopyText(exportString, L['Talent Loadout String']);
        return;
    end
end

My wild guess is that it has something to do with self.talentBuildLinksSupported.
It is never set and it isn't in the SavedVariables.

fixed in next update