Relationships only working for certain years.

Hello Everyone I have two datasets "Registration" and "Demo" that both share the column YEAR. Both YEAR variables have the years 2017, 2019, 2021, 2023. I created a Many to Many relationship between them so when a filter is selected on "Registration" YEAR it will aslo filter that year in the "Demo Data". For some reason if 2017 or 2019 are selected it will show the corresponding "Demo" data as expected. However, if 2021 or 2023 are selected all of the visualizations for "Demo" just blank out. Any ideas?

I have also tried a similar relationship on a primary key column and the same thing happens, the data will only populate for 2017 and 2019 but not 2021 and 2023.