Is there a reason you're still on CC 2017? There have been countless features, bug fixes, and performance improvements, including caption advancements since that version. The simplest thing to try is to open this project in the latest version of Premiere 2020.
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I can find no way to create what you are seeing. Your Caption panel shows the font information "lit up." If a caption stream has no captions and is selected, the font info is dimmed out.
Also, the caption stream visible on the timeline has the default caption ("Type Caption Text Here"), and we can see the left hand end of a new caption pair, but there is nothing inside it. So I don't know what you are seeing.
Create a new project, create a caption. Does it show correctly in the Caption panel?