This doesn’t makes sense to me.
What you appear to have done is to create quarter-note triplets at the end of the measure (which then hang over into the next measure).
Erase the triplet at the end of the measure, as well as the rests in the next, and type 3:2e in the popover to create a new set of eighth-note triplets.
There were three 1/8s in a triplet before the bar line, and three 1/8s in a triplet after the bar line. I don’t understand why those would be linked. @derrek, I guess I don’t know what you mean about 1/4 note triplets.
If, by mistake, you enter a quarter note triplet on the last (quarter) beat of a bar - i.e. a too long triplet -, Dorico creates two linked eight triplets, one on each side of the barline. That is probably what happened here.
Can you post that part of the project? I tried to replicate the behavior but couldn’t. But there’s various ways to input the triplets so I may not have gone down the same exact path.
If a tuplet is large enough to carry over the bar line (quarter-note triplet on the fourth beat of 4/4 time):
tupletsDorico.dorico (494.9 KB)
If one doesn’t set the rhythmic duration to eighths before creating the tuplet, the program will default to the last known note length–or the default of a quarter note.
Very clear explanation. Thank you.
@sjanssens , Thanks very much for the offer, but I think this is resolved. 
