Ignore formula tag that isn't within a cell

src/main/java/com/monitorjbl/xlsx/impl/StreamingSheetReader.java

@@ -189,7 +189,9 @@ && isSpreadsheetTag(event.asStartElement().getName())) {
           }
         }
       } else if("f".equals(tagLocalName)) {
-        currentCell.setType("str");
+        if (currentCell != null) {
+          currentCell.setType("str");
+        }
       }
 
       // Clear contents cache
@@ -207,9 +209,12 @@ && isSpreadsheetTag(event.asEndElement().getName())) {
         currentRowNum++;
       } else if("c".equals(tagLocalName)) {
         currentRow.getCellMap().put(currentCell.getColumnIndex(), currentCell);
+        currentCell = null;
         currentColNum++;
       } else if("f".equals(tagLocalName)) {
-        currentCell.setFormula(lastContents);
+        if (currentCell != null) {
+          currentCell.setFormula(lastContents);
+        }
       }
 
     }

src/test/java/com/monitorjbl/xlsx/StreamingReaderTest.java

@@ -4,6 +4,7 @@
 import org.apache.poi.openxml4j.opc.OPCPackage;
 import org.apache.poi.openxml4j.opc.PackageAccess;
 import org.apache.poi.ss.usermodel.Cell;
+import org.apache.poi.ss.usermodel.CellType;
 import org.apache.poi.ss.usermodel.DateUtil;
 import org.apache.poi.ss.usermodel.Row;
 import org.apache.poi.ss.usermodel.Workbook;
@@ -671,4 +672,25 @@ public void testShouldHandleBlankSSTReference() throws Exception {
       }
     }
   }
+
+  // The last cell on this sheet should be a NUMERIC but there is a lingering "f"
+  // tag that was getting attached to the last cell causing it to be a FORUMLA.
+  @Test
+  public void testForumulaOutsideCellIgnored() throws Exception {
+    try(
+        InputStream is = new FileInputStream(new File("src/test/resources/formula_outside_cell.xlsx"));
+        Workbook wb = StreamingReader.builder().open(is);
+    ) {
+      Iterator<Row> rows = wb.getSheetAt(0).iterator();
+      Cell cell = null;
+      while(rows.hasNext()) {
+        Iterator<Cell> cells = rows.next().iterator();
+        while(cells.hasNext()) {
+            cell = cells.next();
+        }
+      }
+      assertNotNull(cell);
+      assertThat(cell.getCellTypeEnum(), is(CellType.NUMERIC));
+    }
+  }
 }