Crossing Staves Bug (maybe?)

Hi, gang!!!

I use MuseScore 3.0.1 portable version with UbuntuStudio 18.04.1 LTS.

I had an score with this layout:

https://musescore.org/sites/musescore.org/files/2019-01/Captura%20de%20…

I wanted to put the first note of the triplets into the F key, using [Control]+[Shift]+[↓], and I got this:

https://musescore.org/sites/musescore.org/files/2019-01/Captura%20de%20…

Well, there are two issues here (I don't know if it is because It is a bug or...):

1) The triplet indicator numbers were put two far of the triplets position.

2) The original whole note silent of the F key staff was not removed/changed.

Is it a bug??? Or... I did something worng???

Blessings and Greetings from Chile!!!

JUAN