Minato has placed the ftg mark on something les say a door and then someone slices the door in half and slices through the ftg mark as well will the jutsu formula be ineffective
If the seal isn't there anymore he cannot teleport there. For instance when madara pulled the kyuubi from naruto he damaged minatos seal aswell as his ftg marking on that seal. That is why minato couldn't teleport to naruto right away because the seal wasn't there. Thats why gaara had to fly naruto to minato. instead of minato just going teleporting there.