diff --git a/crates/engine/tests/it/main.rs b/crates/engine/tests/it/main.rs
--- a/crates/engine/tests/it/main.rs
+++ b/crates/engine/tests/it/main.rs
@@ -23,6 +23,7 @@ mod pivot_unknown_func;
 mod pivotchart_link;
 mod range_fill_formats;
 mod row_autofit;
+mod sheet_copy_spill;
 mod sheet_name_quoting;
 mod sparse_clear_invalidation;
 mod stored_list_shape;
diff --git a/crates/engine/tests/it/sheet_copy_spill.rs b/crates/engine/tests/it/sheet_copy_spill.rs
new file mode 100644
--- /dev/null
+++ b/crates/engine/tests/it/sheet_copy_spill.rs
@@ -0,0 +1,33 @@
+use gridcraft_core::{CellRef, Value};
+use gridcraft_engine::Session;
+use gridcraft_engine::calc::Calc;
+use serde_json::{Value as Json, json};
+
+fn run(s: &mut Session, command: &str, params: Json) {
+    s.execute(command, params).unwrap();
+}
+
+fn value(s: &Session, sheet: &str, cell: &str) -> Value {
+    let wb = &s.doc().unwrap().wb;
+    wb.sheet(wb.sheet_index(sheet).unwrap()).unwrap().value(CellRef::parse(cell).unwrap())
+}
+
+/// Issue #2053: the copy of a sheet holding a spill keeps the spill's values, in memory and after a full recalc.
+#[test]
+fn copied_sheet_keeps_spill_values_through_full_recalc() {
+    let mut s = Session::new();
+    run(&mut s, "file.new", json!({"sample": "grades"}));
+    run(&mut s, "home.mergeCells", json!({"range": "F:H"}));
+    run(&mut s, "cell.set", json!({"cell": "J54", "input": "=SEQUENCE(5)*C6"}));
+    run(&mut s, "selection.set", json!({"range": "15:15"}));
+    run(&mut s, "sheet.move", json!({"copy": true, "sheet": 0, "to": 1}));
+    run(&mut s, "cell.set", json!({"array": true, "cell": "D3", "input": "=SUM('Grades (2)'!J54#)"}));
+
+    let before = value(&s, "Grades (2)", "J55");
+    assert!(matches!(before, Value::Number(_)), "J55 should hold a spilled number, got {before:?}");
+
+    let mut fresh = (*s.doc().unwrap().wb).clone();
+    Calc::new().recalc_all(&mut fresh);
+    let after = fresh.sheet(fresh.sheet_index("Grades (2)").unwrap()).unwrap().value(CellRef::parse("J55").unwrap());
+    assert_eq!(before, after);
+}