I have looked into this issue. It seems that there really is a dotted line between Richard and Marianne, it is just covered by a regular line, that is supposed to be from Richard to Cristina.
This is a bug that we are aware of, that three marriages/divorces are not shown properly in this chart.
We are working on fixing this for future versions.
We apologize for the inconvenience.
Esther / MyHeritage Team