diff --git a/crates/a11y/src/tests.rs b/crates/a11y/src/tests.rs
index b551c2cb42..a129f207cd 100644
--- a/crates/a11y/src/tests.rs
+++ b/crates/a11y/src/tests.rs
@@ -1129,6 +1129,23 @@ fn a_tags_content_in_a_stream_damaged_partway_is_not_rewritten() {
     assert_ne!(list.get(1), Some(&Object::Ref(ObjRef::new(4, 0))), "the tag's stream is rewritten");
 }
 
+/// A content stream that doesn't decode at all is kept as stored, and a tag in the page's other
+/// streams is still marked: only running past the decode budget refuses.
+#[test]
+fn a_tag_beside_a_stream_that_does_not_decode_is_marked() {
+    use pdfcraft_cos::{Dict, ObjRef, Object, Stream};
+    let mut doc = figures_doc();
+    let mut dict = Dict::new();
+    dict.set(b"Filter".to_vec(), Object::name("NoSuchFilter"));
+    let other = doc.add(Object::Stream(Stream::from_raw(dict, b"0 g".to_vec())));
+    doc.update_dict(ObjRef::new(3, 0), |p| p.set(b"Contents".to_vec(), Object::Array(vec![Object::Ref(other), Object::Ref(ObjRef::new(4, 0))])))
+        .unwrap();
+    mark_tag_artifact(&mut doc, ObjRef::new(7, 0)).unwrap();
+    let contents = doc.get(ObjRef::new(3, 0)).as_dict().unwrap().get(b"Contents").cloned();
+    let Some(Object::Array(list)) = contents else { panic!("contents {contents:?}") };
+    assert_eq!(list.first(), Some(&Object::Ref(other)), "kept as stored");
+}
+
 fn ref_(n: u32) -> Option<pdfcraft_cos::ObjRef> {
     Some(pdfcraft_cos::ObjRef::new(n, 0))
 }
diff --git a/crates/edit/src/tests.rs b/crates/edit/src/tests.rs
index 2f7a310648..dc80cb6a29 100644
--- a/crates/edit/src/tests.rs
+++ b/crates/edit/src/tests.rs
@@ -5198,6 +5198,26 @@ fn an_edit_never_rewrites_a_content_stream_damaged_partway() {
     assert_eq!(kept.raw, damaged.raw, "stored as it was");
 }
 
+/// A content stream that doesn't decode at all is no damage to write over: it is kept as stored,
+/// and the page's other streams are read and edited around it. A stream of a few MB is read for
+/// selecting objects.
+#[test]
+fn a_content_stream_that_does_not_decode_is_kept_and_edited_around() {
+    let mut doc = split_page("", "BT /F1 12 Tf 72 600 Td (Whole) Tj ET");
+    let mut dict = pdfcraft_cos::Dict::new();
+    dict.set(b"Filter".to_vec(), Object::name("NoSuchFilter"));
+    let unknown = pdfcraft_cos::Stream::from_raw(dict, b"BT /F1 12 Tf 72 700 Td (Unread) Tj ET".to_vec());
+    doc.set(pdfcraft_cos::ObjRef::new(4, 0), unknown.clone());
+    text::replace_line(&mut doc, 0, 0, "Edited").unwrap();
+    let doc = reopen(&doc);
+    assert_eq!(text::text_lines(&doc, 0).unwrap().into_iter().map(|l| l.text).collect::<Vec<_>>(), ["Edited"]);
+    let Object::Stream(kept) = &*doc.get(pdfcraft_cos::ObjRef::new(4, 0)) else { panic!("not a stream") };
+    assert_eq!(kept.raw, unknown.raw, "stored as it was");
+
+    let large = format!("{}0 0 m 10 10 l S", " ".repeat(2 << 20));
+    assert!(editable_objects(&split_page(&large, "BT /F1 12 Tf 72 600 Td (Whole) Tj ET"), 0).is_ok());
+}
+
 /// Objects are selected only from content read whole: what a damaged stream hides past the
 /// damage could change the graphics state of every later item.
 #[test]