GIF bug

I created a post that would schedule to post to Facebook and Instagram. I added photos and a gif. There were no errors. I submitted and the post went live at the right time, but the gif did not move. it was stuck on one image. I checked the gif I uploaded and it does move and the format is .gif. But on instagram it appears as just a photo. The weird thing is in the preview on Adobe Express it moved. So it made me think it would also move in the post.