Arpeggios have inconsistent speed

When adding an arpeggio to a half-note (this:)

, the arpeggio lasts longer than when adding an arpeggio to an eight note tied to a longer note value:

Here, the arpeggio gets sped up drastically.
I understand how this could have happened, but in my opinion it should be fixed.

When playing tied notes (when playing a real instrument), the tied notes should be treated as ONE duration. Thus, the duration of the first note of the tie-bundle does not have any impact on playing techniques. Yet in Musescore it currently does.

Score for demonstration:
Arpeggios_Broken.mscz