I tryed animate position of object, but it behaves unpredictably!

[timofax]

A very simple task: appear from the left, move slowly across the screen from left to right, fast leave to the right. When I put 4 markers (1 - left, outside screen area, 2 - in the screen, where the slow moving must starting, 3 - where the slow moving must finished, 4 - right side outside screen area), the odject moves to point #1, after it to point #2, after it to point #3... BUT IN THE MIDDLE OF THE WAY! It inexplicable start moving BACK, after few frames ruturnes to moving in correct way. How can I fix it? Why it happens?!! Here is exapmle: https://youtu.be/D_RXKIHNDXk

[SamLanes · Accepted solution]

This looks like one or more of the keyframes are set to 'autobezier'. To change this, highlight all of the keyframes, right click, and in both Temporal- and Interspacial Interpolation, the option for 'Linear' is selected.

[timofax]

No! I checked this - all of them set to "linear". But I also find one more interesting thing: if I turno on visibility of the path of moving on program monitor, in the center I can see DOUBLE line, and if I zoom it to maximum, I understand, that it looks like "pressed to bottom" "Z". Why Premiere creating not STRAIGHT path - I can't understand. 

UPD. Sorry, you were right. But I still don't undersand why. So, now I can fix it! THANK YOU!!!!!

P.S.: first time I don't paid my attention for "select all" and "both" menu points.