If a unit that is already mighty loses mighty status and then gains it back, can Fiora - Worthy's effect (readying a unit when it becomes mighty) trigger?

Ruling: Yes, Fiora - Worthy's effect can trigger when a unit loses mighty status and then gains it back.

Sequence:

• Control Fiora - Worthy and an exhausted, buffed Fiora - Victorious
• Cast Call to Glory on the buffed Fiora - Victorious, spending the buff for cost
• Fiora - Victorious loses mighty status (loses the buff)
• Call to Glory resolves, giving Fiora - Victorious mighty again
• Fiora - Worthy's effect triggers, allowing you to ready Fiora - Victorious