Pantheon's Stun

Multiple times while playing as Fiora in 1 game a Pantheon jumped to me and I became stunned. I know thats how the ability works, but on multiple occasions I waited for him to start the jump and I either flashed away or used Fiora's Q to dash out of range. Upon his landing from the jump even when I was at a safe distance thanks to my flash and or Q I was stunned after my abilities gave me significant distance and he was able to close the distance again by running up to me while I was stunned after he missed his ability due to being out of range. I have multiple issues with this scenario.

1st issue: If he activates his ability and I get far away while he is in mid jump I shouldn't be stunned especially after I used my Flash or other distance covering abilities.

2nd issue: If the ability is programmed to stun once activated anyway, my flash that was consumed for nothing should be refunded or not even be usable if I'm locked on via point and click abilities that stun.