[kguen21]

Wheneve I flush the toilet the flapper flips the whole way over instead of resetting into position.

[Milo Dolezal]

You may have a wrong flopper installed. Usually, flopper has a fin - a high point - on its back that hits the overflow tube when elevated. That fin bounces it back as water empties tank, and flopper lowers itself into closed position

Also, newer toilets use floppers with Styrofoam float. It is either hanging on the chain, or it may be part of the flopper itself. It may be that it got loose and flushed down the toilet

If you have the Styrofoam on the chain, it may be too high. Push an inch down ( or as needed ). That will help the flopper to close as water empties tank

If nothing works, than look what brand and model number toilet you have. This information is printed on the inside of the toilet tank and / or lid. Take this information and Google it. It tells you exactly what flopper your toilet need. Write this information down, go to Home Depot and buy that exact flopper

Hope that helps

Milo