I noticed this behavour today also.
I am confused as to why when you select a DIR TO the TMPY FPLN comes up on the 2nd MCDU.
I think when you have an additional DIR TO you need to clear the previous one from the box of the DIR page, in the case of your video delet SVL
I had the same issue where the 2nd DIR cleared my entire flight plan, BUT, I was able to get it back with out with some missing parts by clearing the previous DIR fix from the LSKL1 box on the DIR page and inserting the new DIR waypoint.