Based on your screenshot having the metric "people" I'm assuming you're using CJA and not Analysis Workspace? I've only used CJA a little bit, but I attempted to build something similar. I made a table and a line graph from it, and then did a filter on the table, but the line graph didn't change. So I was able to replicate the same issue that you're having. I tried the same thing in Analysis Workspace, and wasn't able to replicate it, the filter impacted the table and the line graph correctly.
I don't know enough about CJA to know if this is a bug or a feature. But given the fact that it doesn't do the same thing in Workspace, I think it's a bug. I would recommend sending in a ticket to client care, include screenshots of the table and graph both before and after adding the filter, to show that it isn't changing. Hopefully they can help you figure out what is happening.
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