Error:-[libx264 @ 000001fa2ffdd080] height not divisible by 2 (244x207)
Use

ffmpeg -y -i audio.mp3 -loop 1 -i image.jpg -filter_complex "[1:v]scale=2*trunc(iw*sar/2):2*trunc(ih/2)[bg];[0:a]showwaves=s=1280x175:colors=White:mode=p2p,format=yuv420p[v];[bg][v]overlay=0:200[outv]" -map "[outv]" -pix_fmt yuv420p -map 0:a -c:v libx264 -c:a copy -shortest output12.mp4

Since the image is the base layer, its dimensions should be made even.