Nah. Easy fix. Break all the tiles apart and clean off the grout. It should scrape off with a little effort. Then clean any loose dry adhesive off the stair. Get as much off as you can. You can purchase new tile adhesive and a small tube of grout at your local hardware store. Apply a layer of the new adhesive to the stair with a putty knife. Then set the clean tiles in place. They should squish into place but not so much that the adhesive fills the gaps between. Let them sit and allow the adhesive to cure overnight. Then squeeze in enough new grout between the tiles until it’s a bit overfilled. Use a grout squeegee and run it across all the tiles at once to remove the excess leaving it flush with the tiles. Then smooth it all to match the existing with a damp sponge. Remove the left behind haze from the grout after waiting a few minutes. If you don’t want to buy a grout squeegee since this is such a small area use whatever you have that is rubbery and rigid yet flexible like a cooking spatula. Once it dries for about a day polish to a nice shine. Boom done.