FFMPEG image not updating - ffmpeg

Question

THE INPUT FILES
An overlay image that has is being updated every 5 seconds by a Python script
A small MP4 file that will be looped by a concat input
An MP3 file as audio source
THE COMMAND (UPDATED)
This is the command I'm currently using to combine and stream the inputs.
ffmpeg -re -i music.mp3 -f concat -i videoincludes.txt
-r 1 -loop 1 -f image2 -i overlay.png
-c:v libx264 -c:a aac -shortest -crf 23 -pix_fmt yuv420p
-maxrate 2500k -bufsize 2500k -preset ultrafast -r 30 -g 60 -b:v 2000k -b:a 192k -ar 44100
-filter_complex "[1:v][2:v] overlay=0:0" -map 0:a -strict -2
-f flv rtmp://a.rtmp.youtube.com/live2/{key}
Als tried using -framerate 1 instead of -r 1
THE ISSUE
So the issue is that the image doesn't always update. Sometimes it does update every couple seconds at the start but it stops updating after 10-20 seconds without any difference in log output and sometimes it just doesn't update.
I can however confirm that the image is being updated by the Python script but FFmpeg is just not picking this up.
I read setting the input format of the image to image2 should allow it to update so I am not sure what is wrong or what I can do to improve it.

Answer 1

I'm working on the same task, and finally, I think, I found the answer.
Because streams different from each other we must reset their timestamps with setpts=PTS-STARTPTS to have them begin in the same zero timestamp . And, also, try to use image2pipe instead of image2.
This is your code with timestamp reset:
ffmpeg -re -i music.mp3 -f concat -i videoincludes.txt
-r 1 -loop 1 -f image2pipe -i overlay.png
-c:v libx264 -c:a aac -shortest -crf 23 -pix_fmt yuv420p
-maxrate 2500k -bufsize 2500k -preset ultrafast -r 30 -g 60 -b:v 2000k -b:a 192k -ar 44100
-filter_complex "[1:v]setpts=PTS-STARTPTS[out_main]; [2:v]setpts=PTS-STARTPTS[out_overlay]; [out_main][out_overlay]overlay=0:0" -map 0:a -strict -2
-f flv rtmp://a.rtmp.youtube.com/live2/{key}
p.s and I think, there is no need in -r or -framerate anymore