It was discussed earlier that it may be some kind of exclusivity bug between Sprint and LD-Haste. It seemed to be greyed out if any part of LD was twisted, or if LD was active, wheter or NOT LD haste had been trained. Now it seems worse: If Ranger Sprint is trained, it will not work in any way, LD twisted/active or not. What's more, if Ranger Sprint is trained, ANY switch in active destiny causes the entire Tempest tree to reset to zero.
Bug reported.