Is this junction at Risk. Should I support this jo...

It is not at risk unless you bend down the corresponding branches too far. I had the same problem on a larger plant, I thought the stress would force my plant to go into flower earlier, this did not occur of course. Some temporary reinforcement is recommended like taping it to stop the spread. I say temporary because reinforcement to the branches can sometimes constrict them and cause bulges on both sides of the tape, causing the taped portion to stay slender and weaker. It has outgrown every other plant.