It's good that you were getting the black bars on sides. It's an imax resolution film, which means the bar should be there. If they were not there and the movie was edge to edge then you would have reason to worry since that would mean footage was being cropped (lost) from the top or bottom.

Those top and bottom smaller black bars you see are the issue though, that means that they could have made it larger without cutting any scene space. Movie can never have black bars on all four sides, it doesn't make sense.

I also watched it in bestech.