Why closing a Calc file after saving takes too long?.

I have a Calc file that contains some formulas and formatting.
The file size is 12.6MB and it takes 2 seconds to load and calculate on my computer. If I work on the file, save and then close either by clicking on the “X” on the window or by selecting “Close” on the menu. When I do that it just stays there, the hard drive light on my computer stays inactive and nothing happens for a long time (about 20 minutes) during this time I cannot open or work on other Calc files. I can use other programs without any issues.
Also if I open the Calc file and close it without saving or making any changes the same thing happens.
I am using Ubuntu 18.04.4 LTS 64bit
LibreOffice Version:
On an Intel® Core™ i7-6700HQ CPU 15GB RAM and GeForce GTX 960M and SSD Drive.
I tried renaming the User Profile, installing the newest versions of LibreOffice, installing on a different computer and no luck.
I also noticed the files that take too long to close have about 80K rows. I have other files with less than 200 rows but are heavier in terms of formulas and formatting that close pretty quickly in comparison.
I can also see a lot of people have been having this issue on previous versions and it has not been resolved. Any help solving this issue would be greatly appreciated!