Issue with Excel Power Query

In my excel workbook I have a long string of queries to get the results I want, however I am noticing a small number of duplicates that SHOULDNT be able to exist.

In my first query in this string, I am adding a new column (SelectionBucket), based on two other columns - Works. Then taking this SelectionBucket column, and adding another column (IsRequiredBucket) based on [SelectionBucket] returning one of the required values - Works. I then am adding an index at this time (CourseIndex) - Works.

Result: Courses have Index, and SelectionBucket and IsRequiredBucket as options.

Q2 (Reference to Q1): Adding Column (IsRequiredCandidate) where [IsRequiredBucket] = True - Works.
Filters out to ONLY true values next, and sorted on (Name) (Ascending), (SelectionBucket) (Ascending), (EMark) (Decending) - Works.

Result: Filtering down to only RequiredBuckets, sorted by Best to Worst.

Q3 (Reference Q2): I group the rows based on (Name) and (SelectionBucket), call it [AllRows]. Add Column (TopRequired) with Table.FirstN(Table.Sort([AllRows], {{"EMark",Order.Descending}}),1) to return the BEST value - Works. Expand the [TopRequired] Table, excluding Name and SelectionBucket - Works. Add column (SelectionType) = "Required"

This is where I am not sure if it is working or not, because for 99% of my data, this works. But for some of the entries, this isn't working.

Add one more column (IsRequiredSelected) to check (SelectionType), if "Required" = TRUE.

Result should be: Selection of one result for each of the buckets available per entry, and setting its (IsRequiredSelected) value to TRUE.

Q4 (Reference Q1): I merge Q4(which is just Q1), to Q3, matching on (CourseIndex), Expand the merge (SelectionType). Rename (SelectionType) to (RequiredTag). Add column (IsRequiredSelected) checking [RequiredTag] to return TRUE for "Required", FALSE otherwise.

Q5 (Reference Q4): Add Column (IsAdditionalCandidate) checking [IsRequiredSelected] = FALSE. Filter (IsAdditionalCandidate) for only TRUE values. Sort by (Name) (Ascending), (EMark) (Descending).

Result: Check if (IsRequiredSelected) = TRUE and clearing them out.

Q6 (Reference Q5): Group by Name -> [AllRows] with operation of All Rows. Add column (TopAdditional) coded =Table.FirstN(Table.Sort([AllRows], {{"EMark",Order.Descending}}),7). Expand the table [TopAdditional] excluding (Name). Add column (SelectionType) = "Additional"

Result: Taking only records that are marked as "Additional" and taking the best 7 results for each (Name).

Q7 is an appended query of combining Q3 and Q6, where it should take the Q3 Results, and adds the Q6 results to it, which should result in NO duplicates.

Issue: I am receiving some of my entries as a duplicate through a query check, where I see the one record as both an Additional and as a Required. I am not sure WHY or where it is broken, other than where I think it is...

I realize I could have done this in less Queries, however I wanted to verify along each step of the way if something went wrong, so that I could fix it as a portion, instead of having to delete and re-write everything.

Please note that I CANNOT share the excel file data itself, as it contains confidential information within it. If I haven't explained a step clearly enough, please let me know and I will try to add further information on it.