Aniamtion only lasts half the keyframes

Its super weird its happening to everything I aniamate in this scene from objects to lattice keys
It has to be a setting of some kind I know it dosent happen if i create a new scene

How many keyframes are entered in the N-Panel Output tab?

where’s that whats the N-pannel output tab?

hello maybe share your file (delete all unnecesary objects):

Under the Right “N” Panel Tab that looks like a Printer…It is where you enter your Resolution and under that is frames and frame rate…( it should be OK as default is 250 Frames, but maybe you changed that at some time).
and like @moonboots said…if you can please share what you can so we could investigate the problem…hard to figure out by guessing…