Graph Only Allows A Specific Filter Value

Hello, I have an odd Power BI issue and am trying to figure out whether it's a bug or a setting that I'm unaware of.

I work in manufacturing and created a graph that has year/month on the x-axis and shows the number of hours it takes to perform a specfic step for a specific P/N on the y-axis (i.e. Step 1 for P/N A took x hrs/unit in May, y hrs/unit in June, etc.).  The primary filters are (1) P/N and (2) Step, and the step filter is in the viewport while the P/N filter is in the filter pane.  I tested the graph out for a specific P/N and it seemed to work fine, but later on I tried other P/Ns and the graph turned blank for every other P/N (note: there are some other filters in the filter pane but all those were cleared).  I ended up resolving the issue by creating a duplicate of the graph in a different page, as it was fortunately pretty simple/quick, but I'd like to figure out what happened in case I run into this issue again.