Vocal track sustain glitch?

So I'm writing on a vocal track pretty much for the first time, and I'm wondering if this is an issue other people have. Whenever I play through my song, if there's a note longer than 1/8 and there's a note after it within the bar, it does this weird sustain thing where a dotted eighth note sounds like two separate eighth and sixteenth notes (bar 27), or a quarter note before an eighth note just sounds like 3 eighth notes (bar 23). If the note is alone in the bar though (like at the end), it sounds normal, but I think it might still be doing the thing, it's just less noticeable when it's not connecting to the next note. Is there an actual glitch at play here or is it possibly just a weird audio illusion? I've always found the tone they use for vocal tracks to be annoying, but this issue is actually distracting so if anyone knows how to fix this I'd appreciate it.