"Conflict: The following destination is shared by multiple files." error after Jekyll Build

The problem

I'm running into a conflict error and a strange issue where my Homepage title is modified and "- Page 2" appears in the tab itself when I place a certain post inside the _posts folder. When I take this specific post out, the problem is resolved. The blog post itself works properly and I'm not encountering other issues. I'm running Minimal Mistakes theme and I'm knitting .Rmd reports in RStudio with GitHub flavored markdown.

Link to my main repo
Link to the specific post inside repo
Link to config.yml

YAML header for knitting .Rmd

title: "Data visualisation"
date: "`r Sys.Date()`"
output: 
  md_document:
    variant: gfm

Knitting options for Rmd

library(knitr)

# macOS
# setwd("~/Developer/mkruisbrink.github.io/_reports/R-for-data-science/01-explore/01-data-visualisation/")

# Windows
setwd("D:/Max Kruisbrink/Developer/mkruisbrink.github.io/_reports/R-for-data-science/01-explore/")


knitr::opts_chunk$set(echo = TRUE)
knitr::opts_knit$set(root.dir = rprojroot::find_rstudio_root_file())

# define knitr paths for macOS
#base.dir <- "~/Developer/mkruisbrink.github.io/"

# define knitr paths for Windows
base.dir <- "D:/Max Kruisbrink/Developer/mkruisbrink.github.io/"

base.url <- "/"
fig.path <- "assets/reports/R-for-data-science/01-explore/01-data-visualisation/"

# set knitr parameters
opts_knit$set(base.dir = base.dir, base.url = base.url)
opts_chunk$set(fig.path = fig.path) 

I get a neat .md file which I can place inside my _posts folder with some yaml header. All other posts are processed fine, the error only appears when I place this specific post inside the folder.

YAML header for post

title: "The basics of data visualisation in R"
excerpt: "These are the basics of visualizing data in R, using only the tidyverse functionality"
header:
  overlay_image: /assets/images/midjourney-optimised/big-computer-screen-financial-dashoard-optimised.jpg
category: 
  - Exploration

What I've tried so far

I've tried the following:

• Spent at least 2 hours on online research, didn't find any proper relevant sources to help me out here
• Manually removing from and adding back all posts from the _posts folder to figure out the problem lies with this specific post
• Running bundle update and bundle install
• Double checking YAML headers for posts and the config file
• Checking .Rmd settings for other reports that are knitted in the same way and cause no issues
• Removing the post content from the .md file to see if the bug came from something in the code perhaps
• Replacing the whole YAML header with that of a post that causes no issues
• Ran --trace in combination with bundle exec jekyll serve for the same conflict results
• Ran --verbose in combination with bundle exec jekyll serve and I could find ONE extra instance of something writing index.html to _site. So the following appears twice in the log. I know the culprit is this post but how to get more info on what is causing it?

Writing: D:/Max Kruisbrink/Developer/mkruisbrink.github.io/_site/index.html

Conclusions and questions

I'm starting to run out of options for my current skill level of debugging.

• Could it be something relating to _includes or _layouts? I might have tweaked layouts but pretty sure I left the includes folder alone. But why would other posts be unaffected?
• Could it be plugin related? I had no problems up until last week suddenly and didn't change any plugin.
• Should I update to the latest theme, removing any customization I've done to rule that out
• I'm running this in my gemspec

source "https://rubygems.org"
gemspec

    gem "webrick"
    gem "jekyll-remote-theme"
    gem "tzinfo" #windows dependancy?  
    gem "tzinfo-data" 

Can someone point me in a direction here? Getting slightly clueless and I want to be a little cautious with my re-rolling. Thanks in advance!