I would suggest that in the long term it makes sense to fully understand how Dorico behaves and how a used VSTi behaves.
Otherwise one may always encounter some problems.
Assuming you choose in the setup mode of Dorico a bass instrument (like double bass or electric bass), Dorico notates the bass track correctly one octave higher than it sounds.
Dorico plays (sends midi) the bass track correctly one octave lower than it notates it
Now which octave a VSTi is playing depends on the VSTi, there is unfortunately no rule, one has to verify this.
It means that to get the right octave from Dorico to a VSTi you have to first make sure that the VSTi plays the right octave and does not transpose on its own.
For example it is known that HSO itself transposes bass instruments one octave lower.
This leads of course to the wrong octave when you play HSO from Dorico if you do not take care of this.
Luckily in the meantime Dorico offers specific Expression Maps" for HSO where it has been taken care of this.
If you want to use a HSO bass instrument in Dorico you have to also use the appropriate “Expression Map”.
If you look at a HSO “Expression Map” for double bass for example you will see that the transpose setting is set to 12.
This indeed compensates the fact that in HSO itself a bass instruments sounds one octave lower.
Of course it is nice that Dorico provides an appropriate Expression Maps for HSO bass instruments but it is usefull to understand why it works.
The ARIA player for example does not transpose, it sounds at the right octave.
I do not have the Scarbee Bass so I do not know if in itself it sounds at the right octave.
Dorico behaves correctly but a VSTi may not, therefore it is important to check how the used VSTi behaves and eventually create an apropriate Expression Map.
After a quick test I notice that the Factory Pop Bass in Kontakt 6 sounds an octave lower, it suggests that possibly the Scarbee Bass also sounds an octave lower.
If you happen to use the HSO Bass Expression Map with this instrument in Dorico (which is possible if you previously used the HSO Electric Bass) it will indeed lead to a double transposition.
In this case use the default expression map or make a copy of the HSO expression map and get rid of the transposition.