That's really weak.

They can do better.

A 2x spanning that space and use a joist hanger. Also, nail that spanner into the end of the beam.

I'd see what the local division of inspection requires. It needs a properly installed joist hanger at a minimum.

With a 'fail' like that on a project, you should look for others.

Need to see more. I see about 2' of 2x6.

Simple solution is to remove the questionable 2X6 and add a new 2X6 fully resting on the double plate, on each side of the existing triple member.

The simpleist solution is to leave the questionable 2X6 where it is and add a new 2X6 fully resting on the double plate, on each side of the existing triple member.

The flooring joints above may need to land on that member in that position. A doubled 2x could be run between the adjacent joists with hangers on each end and the joist attached to them with a hanger.

The best way is to tear the house down and start over.

(exploring every alternative)

Those beams ran long. Look at the other end.

Charles Ross Homes: "...sister a single 2x..." By coincidence this is precisely what I proposed and they agreed to do.