Hi @achits! Welcome!
To help people understand your problem, it's a good idea to provide the R Markdown source, not just the output (when doing so, please be sure to format it properly
so the forum doesn't garble it 
).
It's even better if you can post a small, reproducible example (so, one that doesn't rely on a large data object only you have). I'm not familiar with seurat objects myself, but I wonder if you see the same issue if you use the sample data object from the Seurat "Get Started" page?