Yesterday's Enterprise has a strong enough plot but I second guess Guinan revealing to Tasha that she is dead and also Picard approving her transfer to Ent C is hypocritical if you're trying to restore the timeline (but that was done so Tasha could appear in later episodes)
Though, all it probably created was a stable time-loop, meaning that version of Tasha had always returned to the 23rd century and had always mothered Sela.