Glissandi not playing back correctly

I was working on an existing piece this morning after I had updated to 4.2. When I reopened it just now, a section I had written to blend smoothly from note to note was playing back completely differently, and essentially skipping over glissandi. I saved the impacted selection into the file below. Every time it encounters a glissando it just pauses then plays the next note.

To play around with it, I copied it into a new test file (also included), and oddly two instruments sort of fixed themselves, but the violoncello continued to skip the glissandi (and it still won't play like it originally did).

I will note that I did not tie the second 8th note of each pair to the following note - it didn't need to be tied to sound smooth - but now I hear the pause there in addition to the pause where the glissando is. Notice how measures 8-9 and 10-11 (which don't have glissandi on each instrument), sound very smooth, despite repeating the same note. The whole thing used to sound that way, and I would love to get it back.

Any thoughts?