Matrix hiding records when using time intelligence, unless filtered. Table visual works fine.

Hello, wondering if anyone can help:

When using a matrix to compare Actuals with Prior Year via SAMEPERIODLASTYEAR, some categories of data are being hidden, but still included in totals.

I am using a marked date table created with CALENDARAUTO(3), and all relationships to my Data table are one>many, unidirectional filtering. The issue appears to occur when a category has no data in the selected year but does have data in the Prior Year. However:

• Not all categories with the above criteria are missing - see 'new entities' in screenshot. There really are no rows of data here in Current year.
• When I begin to filter the sub-categories, at some point of filtering the missing category reappears again.
• Everything works fine in a table visual, so the issue seems specific to matrix.
• My data only includes 1st of month dates, but my date table includes all dates.

My TI formula used in "Comparator":

CALCULATE(

[Act 000s], //<this is SUM ('Data All'[Actual])/1000

ALL ('Dates'[Date]),

SAMEPERIODLASTYEAR('Dates'[Date])

)

 

Screenshots:

PY shows correct totals but not everything they comprise:

Selecting the PY directly via the filter (which is a custom column in Date table) shows what was missing above:

If I go back to screenshot 1 and filter on subcategores/data in certain ways, I can get the missing categories to re-appear:

 

In contrast, the table visual seems to work fine:

 

I am unsure if this is a bug of some sort or whether I am missing some TI quirk, but I'm currently out of ideas. Thanks in advance for any help.