PDF convert does not distinguish between ties & slurs

In all the pieces I convert (French horn), all the ties & slurs simply become slurs. French horn (and, I assume, other instruments) can have either ties or slurs (or phrase markings; they all look the same). As a rule, if a mark links two of the same notes (even across bar lines), then, it’s a tie; otherwise, it’s a slur (or phrase mark). When I convert pieces, I have to go through and replace many of the slurs with ties to make the rhythms correct in playback. I understand that MuseScore is primarily for printing & that playback is a nice feature that has been added in, but I use it a lot for rehearsal.