Relationship not Finding Matching Data after Data Source Change

Hi All, I am working on an issue I am running into on one of my client's reports. He has built a simple Daily Cash Report that pulls in data from a spreadsheet and then a date table from a Power BI dataset. The dataset is pulled in using a DirectQuery to AS - Power BI Dataset, but the client is having issues with using this date table because he is pulling it from a dataset that has a high level of security on it, so people in his team are not able to view it because they do not have the right permission to view it. So, I was trying to change the data source from that dataset to another from the data warehouse we built for them with fewer security restrictions. I changed the source to the data model connected to the data warehouse with no issues, but when I went to generate a new relationship for the two tables on their date keys, the new date table did not display any matching data, despite the fact that I have checked to ensure the keys were both the same data type and written in the same way (YYYYMMDD). I am also changing the relationship from one-to-one to one-to-many for best practice purposes, but even when I tried the one-to-one with the new table, it still displayed blank.

Old Relationship: 

New Relationship:

Any help would be appreciated.