Can you provide some self-sufficient sample code which creates the file and then demonstrates the problem? Or at least a sample file? 

This would make it much easier for others to reproduce the issue.

Created attachment 38707 [details]
Eclipse demo project

Thanks for quick response.

The attached Eclipse project has two demo JUnit tests: one which runs OK and another with EXCEPTION.

The first one I created from scratch - and it worked!
Another is crafted from my minimized code with exception present.
The critical code seems to be identical in both...

Option to try: remove comment from cell in ExcelDemo-EXCEPTION.xlsx and the file will load without exception.

added test in r1911399

this test passes so the issue is not reproduced

bug66827.xlsx is the 'excpetion' xlsx from the attachment

This error message now shows up in https://ci-builds.apache.org/job/POI/job/POI-DSL-1.17/lastFailedBuild/testReport/junit/org.apache.poi.stress/TestAllFiles/Extracting____2399_spreadsheet_bug66827_xlsx_XSSF/ and https://ci-builds.apache.org/job/POI/job/POI-DSL-Windows-1.17/lastFailedBuild/testReport/junit/org.apache.poi.stress/TestAllFiles/Extracting____2399_spreadsheet_bug66827_xlsx_XSSF/ so it seems it only reproduces in certain combinations, e.g. only with JDK 17?

So the issue is not with the comments table. It is with the VML Drawing XML.

xl/drawings/vmlDrawing1.vml

has this

<x:ClientData ObjectType="Text">

and this is what is not parsing

According the XSD that POI was built with, only these Object Types are valid.

    Enum BUTTON = Enum.forString("Button");
    Enum CHECKBOX = Enum.forString("Checkbox");
    Enum DIALOG = Enum.forString("Dialog");
    Enum DROP = Enum.forString("Drop");
    Enum EDIT = Enum.forString("Edit");
    Enum G_BOX = Enum.forString("GBox");
    Enum LABEL = Enum.forString("Label");
    Enum LINE_A = Enum.forString("LineA");
    Enum LIST = Enum.forString("List");
    Enum MOVIE = Enum.forString("Movie");
    Enum NOTE = Enum.forString("Note");
    Enum PICT = Enum.forString("Pict");
    Enum RADIO = Enum.forString("Radio");
    Enum RECT_A = Enum.forString("RectA");
    Enum SCROLL = Enum.forString("Scroll");
    Enum SPIN = Enum.forString("Spin");
    Enum SHAPE = Enum.forString("Shape");
    Enum GROUP = Enum.forString("Group");
    Enum RECT = Enum.forString("Rect");

I added a workaround in r1911407