Strange behavior by the trill line with ties.

The first 6 notes in the attached sample are typeset with ties, the second 6 with slurs. On the first set the trill is interrupted at the end of the first note and returns only for the last note. On the slurred set the trill line trills all the time. I don't know if this is known.

With this particular font the ties and slurs look alike but this is not true for every font and there might be a slight problem.