Rollup formula of formula field to return date (running into issues)

[Cormac_Martinez]

Hello! I’m trying to create a really simple roll up field that spits back the max(value) for dates in another table. I have looked at other posts for recommendations, but continue to get 0’s. I think the issue is that the date field the roll up field is pulling from is a formula itself (date another field was last modified). So my question is, how can you do a rollup formula on another formula field? Or am I missing something else?

Thanks!