FFMPEG create zoompan shaky or jittery [duplicate]

I want to create 5 second mp4 video from 1 image.

When I use below code the video is smooth. Default direction is zoom in to top left.

ffmpeg -loop 1 -i prop1.jpeg -vf "zoompan=z='min(zoom+0.0015,1.5)':d=125" -c:v libx264  -t 5 -s "800x450" fade.mp4

So, to zoom in to top right I figure it out to use the code below

ffmpeg -loop 1 -i prop1.jpeg -vf "zoompan=z='min(zoom+0.0015,1.5)':x='if(gte(zoom,1.5),x,x+1)':y='y':d=125" -c:v libx264  -t 5 -s "800x450" fade.mp4

It is zooming in to the right direction but the video become jittery.

Also got some error when converting :

[swscaler @ 0x429bda0] deprecated pixel format used, make sure you did set range correctly
[swscaler @ 0x429bac0] deprecated pixel format used, make sure you did set range correctly
[swscaler @ 0x429bac0] Warning: data is not aligned! This can lead to a speedloss
[swscaler @ 0x429bac0] deprecated pixel format used, make sure you did set range correctly
Last message repeated 97 times
[output stream 0:0 @ 0x37af200] 100 buffers queued in output stream 0:0, something may be wrong.
[swscaler @ 0x429bac0] deprecated pixel format used, make sure you did set range correctly
Last message repeated 24 times
[swscaler @ 0x42b7040] deprecated pixel format used, make sure you did set range correctly
Last message repeated 1 times

What is wrong with the code?

Use upscale before zoompan:

ffmpeg -loop 1 -i prop1.jpeg -vf "scale=8000:-1,zoompan=z='min(zoom+0.0015,1.5)':x='if(gte(zoom,1.5),x,x+1)':y='y':d=125" -c:v libx264  -t 5 -s "800x450" fade.mp4

As above in the comments: this seems to be an ffmpeg bug: https://trac.ffmpeg.org/ticket/4298

Found this workaround here: ffmpeg: smooth zoompan with no jiggle