diff --git a/crates/doc/src/placed_document.rs b/crates/doc/src/placed_document.rs
index 310d7b784..33eccb178 100644
--- a/crates/doc/src/placed_document.rs
+++ b/crates/doc/src/placed_document.rs
@@ -559,6 +559,9 @@ impl Document {
             reads += usize::from(read_full && depth > 0);
             let full = if read_full { full_bytes(&p, &blob) } else { None };
             if full.and_then(|b| read(&p, &b)).is_none() {
+                // A full read cached for another caller (one allowed to read the file) must not
+                // stand in for the one refused or not tried here: the preview shows instead.
+                cache().entries.remove(&(p.key.clone(), false));
                 let preview = if blob.is_proxy() { Some(blob.bytes.clone()) } else { blob.proxy.clone() };
                 if let Some(bytes) = preview {
                     read_preview(&p, &bytes);
diff --git a/crates/engine/src/tests/placed_document.rs b/crates/engine/src/tests/placed_document.rs
index 0ea8fd33b..08071df05 100644
--- a/crates/engine/src/tests/placed_document.rs
+++ b/crates/engine/src/tests/placed_document.rs
@@ -349,6 +349,30 @@ fn native_included_links_keep_missing_placed_documents_editable() {
     }
 }
 
+/// Output prepared by a caller that may not read the placed file shows its preview, not the full
+/// art an earlier caller that could read it left cached.
+#[test]
+fn a_confined_export_does_not_reuse_full_art_read_for_another_caller() {
+    let dir = Folder::new("placed-confined");
+    let other = Folder::new("placed-confined-other");
+    let src = dir.file("src.vectorcraft");
+    source(&src, 100.0, 50.0, BLUE, 0);
+    let mut s = session();
+    place(&mut s, &src);
+    // As a document saved with previews opens: each placed file's blob holds only its preview.
+    for b in std::sync::Arc::make_mut(&mut s.doc_mut().unwrap().doc).images.values_mut() {
+        if let Some(p) = b.proxy.clone() {
+            b.bytes = p;
+        }
+    }
+    let d = s.doc().unwrap().doc.clone();
+    let preview = |d: &Document| d.images.keys().any(|k| k.starts_with(vectorcraft_doc::placed_document::RESOURCE_PREFIX) && k.ends_with("/preview"));
+    assert!(!preview(&d.with_placed_art()), "the file is read in full");
+    let roots = crate::file_access::AutomationRoots::new(&[&other.0], &[]).unwrap().unwrap();
+    let confined = crate::file_access::confine(Some(&roots), || d.with_placed_art().into_owned());
+    assert!(preview(&confined), "only the preview shows");
+}
+
 #[test]
 fn a_document_saved_with_previews_outputs_its_files_art() {
     let dir = Folder::new("placed-preview-output");