Whenever I place a painting, the painting disappears. Later, if I look towards x=0, z=0 in my world, you can see the paintings rise up out of the ground and rise into the sky at high speeds. Curiously, this does not appear to happen with the 1*1, 2*1, or 4*3 paintings, but does happen with the 1*2, 2*2, 2*4, and 4*4 size of paintings. This glitch started when 1.14 came out. I've made sure that there are no command blocks or functions that would teleport paintings in this way.
Can't reproduce. Can you reproduce this on a new world without data packs?