Mon Oct 21 2019 20:56:43 UTC
It's not a bug, it's a feature.
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ID Product Comp Assignee Status Resolution Summary Changed
17197 POI HSSF dev RESO DUPL Cell Formulas , which referring cells written by POI , are not automatically calculated 2004-11-16
21442 POI HSSF dev RESO DUPL values in referencing cells are not updated 2005-03-20
2 bugs found.

as

File a new bug in the "HSSF" component of the "POI" product