diff --git a/README.md b/README.md
index 7bcb853..7c39d6e 100644
--- a/README.md
+++ b/README.md
@@ -158,9 +158,10 @@ read replaces mentions, attachments and macros with text.
 - Text that would read as a marker takes a backslash: `==` wherever it could open or close a
   highlight, `[!…]` opening a quote, and `[x]` or `[ ]` opening any list item, since GitHub reads
   that marker per item.
-- A node read back carries no `localId`, save a `taskList`, `taskItem` or `blockTaskItem`, which
-  Atlassian's schema requires one on: it gets a UUID v4 hashed from the markdown and its position,
-  so the same markdown reads to the same ids.
+- A node read back carries no `localId` except a `taskList`, `taskItem` or `blockTaskItem`, which
+  Atlassian's schema requires one on: each gets a UUID v4 hashed from the whole markdown and its
+  position, the same on every read. Join markdown bound for one document and read it once: the same
+  markdown read twice into one document repeats its ids.
 
 ## The errors