Proplem with Maya 2018 graph editor


Hello everyone. I am a student working from home and i have this problem wiith the graph editor.

I set 2 key frames on frame 1 and 15 and the graph looks like that. If i add more similar result. I alredy talked with my profesor and i dont have a solution.

I tried reseting preferences to default, and i sent the scene to my profesor and he said its normal wiith him. Does anybody know what is the problem?

Thank you all in advance!