Unexpected tab open behavior when "Open declaration source in the same tab" enabled

After a recent update to CLion 2021.2.1,
I experienced a strange effect:
when attempting to open up source files via the Project docker (i.e. the project structure),
I have been unable to create new tabs; when a source file is double-clicked, it replaces the current open tab.
After digging around, I found that the "Open declaration source in the same tab" option was checked,
and after disabling it, I was once again able to open up tabs.
I do not recall enabling this setting prior to the update, and my instance of PyCharm behaves the same way when the option is enabled.
I have two questions:
1. Was this setting set to be enabled in a recent update by default, or was this an issue unique to my installation? Has anyone else run into this issue?
2. Does the description language for this option imply that if one is to navigate to a source file, the replacement would happen?
To quote:
"When you navigate to a method, class or variable, the source file that contains their declaration will replace the current tab if there are no changes."
In this situation, I am not attempting to navigate to a specific method, class, or variable, rather I am looking to navigate to an entire source file.
Thus, since I am not using an option like "Go To -> Declaration", but rather using the file navigator, I would not expect source files to be replaced! As such, the language is unclear to me.
Are source files also meant to be included in the umbrella of navigation actions that are affected by this setting?
I would greatly appreciate any input others have, and if this setting is supposed to behave in such a manner.