SOLVED!!!!... Well, kinda.
Turns out this is a bug that has been present since v13.19 and perhaps has something to do with the .NET 9.0 update. For more information regarding this bug read this forum post:
If you encounter this bug, the only way to get rid of it is to disable startup screens or downgrade to v13.18, the last version where I didn't encounter this bug.
ojed4r's post in BigBox doesn't close properly (or creates a second instance) when having startup screen enabled was marked as the answer