We took a look at your file. Here is a screenshot of the first bar in the PianoRoll where the "staccato" note is heard. There are actually overlapping notes, which would result in it sounding different. I tried dragging the note length so they were beside each other instead of overlapping and it fixed that staccato effect.

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staccato_note.PNG (97.88 KB, 87 downloads)

Best,
Chantelle