Created attachment 160072 [details]
Correct behavior

Created attachment 160073 [details]
Wrong Behavior

Confirmed.
It happens even group for years.

So:
To the sample, add a group for years -> filter for years doesn't work.
After that delete 'Date' field -> filter for years fine.
Add again the 'Date' field -> filter for years fine.

Version: 6.4.3.2 (x64)
Build ID: 747b5d0ebf89f41c860ec2a39efd7cb15b54f2d8
CPU threads: 4; OS: Windows 10.0 Build 19608; UI render: GL; VCL: win; 
Locale: es-ES (es_ES); UI-Language: en-US Calc: CL
Version: 7.0.0.0.alpha0+ (x64)
Build ID: 7459b9ecb54a298f02d19089620149718f8d8d48
CPU threads: 4; OS: Windows 10.0 Build 19608; UI render: Skia/Raster; VCL: win; 
Locale: es-ES (es_ES); UI-Language: en-US Calc: CL

I find a workaround for this issue as follows:
1- edit the pivot table by right click on it and choose Proprieties.
2- Drag the Date field from Filter section to Row Fields. Then click on OK.
3- left click on any cells of Date, then from menu bar select "Data ---> Group and Outline ---> Group".
4- On the "Group by" section select "Years" only.  Then click on "OK" button. 
5- repeat steps 1 to 2 but now return Date field to the Filter Section. Then OK button. 

Now you can filter by year in Drop-down filter.

Unfortunately, there are some flaws in the pivot table especially with date and time. Some testing code:

bool ScSheetDPData::IsDateDimension(sal_Int32 nDim)
{
    CreateCacheTable();
    const ScDPCache::ScDPItemDataVec& rItems = aCacheTable.getCache().GetDimMemberValues(nDim);
    for (const ScDPItemData& rItem : rItems)
    {
        if (rItem.GetType() == ScDPItemData::Type::Date)
        {
            return false;
        }
    }
    return true;
}

However, in initFromCell in dpcache.cxx there is no check for a date/time cell, therefore the above code will not work. In addition, it conflicts with isDataDimension (Data vs Date) and causes a crash. There is even some dead code in dptabsrc.cxx [1] because isDateDimension checks only if the dimension is the first one [2].

[1] https://opengrok.libreoffice.org/xref/core/sc/source/core/data/dptabsrc.cxx?r=f528fff9#1990
[2] https://opengrok.libreoffice.org/xref/core/sc/source/core/data/dpshttab.cxx?r=f477b54e#103

(In reply to Zayed from comment #4)
> I find a workaround for this issue as follows:
> 1- edit the pivot table by right click on it and choose Proprieties.
> 2- Drag the Date field from Filter section to Row Fields. Then click on OK.
> 3- left click on any cells of Date, then from menu bar select "Data --->
> Group and Outline ---> Group".
> 4- On the "Group by" section select "Years" only.  Then click on "OK"
> button. 
> 5- repeat steps 1 to 2 but now return Date field to the Filter Section. Then
> OK button. 
> 
> Now you can filter by year in Drop-down filter.

one more step, make sure the cells are Date not text.

Still open in version: 7.6.4.1

Still open in

Version: 24.2.5.2 (AARCH64) / LibreOffice Community
Build ID: bffef4ea93e59bebbeaf7f431bb02b1a39ee8a59
CPU threads: 8; OS: macOS 14.6.1; UI render: default; VCL: osx
Locale: en-GB (en_GB.UTF-8); UI: en-US
Calc: threaded

With long lists of dates, I find the grouping by year and month offered by 'Autofilters' to be very helpful. It would be nice to have the same facility available in pivot tables.

(In reply to Charles Williams from comment #9)
> Still open in
> 
> Version: 24.2.5.2 (AARCH64) / LibreOffice Community
> Build ID: bffef4ea93e59bebbeaf7f431bb02b1a39ee8a59
> CPU threads: 8; OS: macOS 14.6.1; UI render: default; VCL: osx
> Locale: en-GB (en_GB.UTF-8); UI: en-US
> Calc: threaded
> 
> With long lists of dates, I find the grouping by year and month offered by
> 'Autofilters' to be very helpful. It would be nice to have the same facility
> available in pivot tables.

Did you read comment #4 by @Zayed

As per comment#4 it works because we are putting the group field in the filter, after creating it on fields of PT.

How the filter works in the data source has nothing to do with how it works in the PT.

In the PT dates as showed as text (aligned at left), not as truly dates, this is why it needs to create the group. In fact, when you add a date field to the rows, trying to filter only show dates not the group of years, as in the filters of data table.
And GETPIVOTDATA() function only works with dates if they are introduced in the criteria as text.

So for me not a bug, maybe could be request for enhancement.