I’m working on a bass guitar part with both notation and TAB; I have many slurred grace notes in my music, but I’m noticing those slurs in the TAB connecting the first fingering to the rhythmic stem below the staff…
The problem here is that you’re using different stem directions for the grace notes and the normal notes on the tab staff. By default slurs in Dorico go in the opposite direction to stems, but if you have mixed stem directions then it can’t do this and has to pick one or the other. One possibility would be to use the option at the top of the Slurs page of Engraving Rules to set slurs to always draw above notes, but that would affect your notation staves as well as your tab staves, so it may be easier to set the slur direction in the Properties panel. If you select the first note on the tab staff, then do Select To End of Flow, then Filter > Slurs you can select all the slurs on the tab staff at once.