nested-observe | Object.observe for nested objects | Web Framework library

EDIT Reproducible example at the end.

I found a similar problem described here, but using reactive() doesn't solve my issue.

I'm working on an app where users can upload files with a FileInput, so far it can handle FASTQ and CSV files (focus on CSV here). All uploaded files are saved as RData, which can then be selected in a selectinput where they're loaded again. This selectinput runs basically everything, since after it is evaluated it will trigger some reactive UI to display the CSV. I also noticed when printing that when I select a new file and then select rows it still prints the rows from the previous file.

I started using Shiny this January, I first followed the tutorial on the Shiny page and I've lurked several blogs and StackOverflow questions, so I'm confident that I'm making a ton of mistakes with the reactiveness and other Shiny specific things.

The selectinput observer: