A beam element is a line, so it only touches the cylinder at that line if you use Shared Topology. This is generally an acceptable approximation when the beam width is a small fraction of the cylinder circumference.

If the beam width is relatively large, then you could cut the cylinder on each face of the beam, leave the beam at the true beam centroid with no offsets and use Bonded Contact to connect the beam to the two lines on the cylinder. That would be like two weld lines, one on each side of the beam.