diff --git a/swh/provenance/graph.py b/swh/provenance/graph.py
--- a/swh/provenance/graph.py
+++ b/swh/provenance/graph.py
@@ -199,11 +199,11 @@
     fdates: Dict[Sha1Git, datetime] = {}  # map {file_id: date}
     while stack:
         current = stack.pop()
-        if current.dbdate is None or current.dbdate > revision.date:
+        if current.dbdate is None or current.dbdate >= revision.date:
             # If current directory has an associated date in the isochrone frontier that
             # is greater or equal to the current revision's one, it should be ignored as
             # the revision is being processed out of order.
-            if current.dbdate is not None and current.dbdate > revision.date:
+            if current.dbdate is not None and current.dbdate >= revision.date:
                 current.invalidate()
 
             # Pre-query all known dates for directories in the current directory
diff --git a/swh/provenance/tests/test_consistency.py b/swh/provenance/tests/test_consistency.py
new file mode 100644
--- /dev/null
+++ b/swh/provenance/tests/test_consistency.py
@@ -0,0 +1,95 @@
+# Copyright (C) 2021  The Software Heritage developers
+# See the AUTHORS file at the top-level directory of this distribution
+# License: GNU General Public License version 3, or any later version
+# See top-level LICENSE file for more information
+
+from swh.model.hashutil import hash_to_bytes
+from swh.provenance.archive import ArchiveInterface
+from swh.provenance.interface import (
+    DirectoryData,
+    ProvenanceInterface,
+    ProvenanceResult,
+)
+from swh.provenance.model import RevisionEntry
+from swh.provenance.revision import revision_add
+from swh.provenance.tests.conftest import fill_storage, load_repo_data, ts2dt
+
+
+def test_consistency(
+    provenance: ProvenanceInterface,
+    archive: ArchiveInterface,
+) -> None:
+    # read data/README.md for more details on how these datasets are generated
+    data = load_repo_data("cmdbts2")
+    fill_storage(archive.storage, data)
+
+    revisions = {rev["id"]: rev for rev in data["revision"]}
+
+    # Process R00 first as expected
+    rev_00 = revisions[hash_to_bytes("c0d8929936631ecbcf9147be6b8aa13b13b014e4")]
+    r00 = RevisionEntry(
+        id=rev_00["id"],
+        date=ts2dt(rev_00["date"]),
+        root=rev_00["directory"],
+    )
+    revision_add(provenance, archive, [r00])
+
+    # Register contents A/B/C/b from R01 in the storage to simulate a crash
+    rev_01 = revisions[hash_to_bytes("1444db96cbd8cd791abe83527becee73d3c64e86")]
+    r01 = RevisionEntry(
+        id=rev_01["id"],
+        date=ts2dt(rev_01["date"]),
+        root=rev_01["directory"],
+    )
+    assert r01.date is not None  # for mypy
+    cnt_b_sha1 = hash_to_bytes("50e9cdb03f9719261dd39d7f2920b906db3711a3")
+    provenance.storage.content_add({cnt_b_sha1: r01.date})
+
+    # Process R02 (this should set a frontier in directory C)
+    rev_02 = revisions[hash_to_bytes("0d45f1ee524db8f6f0b5a267afac4e733b4b2cee")]
+    r02 = RevisionEntry(
+        id=rev_02["id"],
+        date=ts2dt(rev_02["date"]),
+        root=rev_02["directory"],
+    )
+    assert r02.date is not None  # for mypy
+    revision_add(provenance, archive, [r02])
+
+    dir_C_sha1 = hash_to_bytes("c9cabe7f49012e3fdef6ac6b929efb5654f583cf")
+    assert provenance.storage.directory_get([dir_C_sha1]) == {
+        dir_C_sha1: DirectoryData(r01.date, True)
+    }
+    assert provenance.content_find_first(cnt_b_sha1) is None  # No first occurrence
+    assert set(provenance.content_find_all(cnt_b_sha1)) == {
+        ProvenanceResult(
+            content=cnt_b_sha1,
+            revision=r02.id,
+            date=r02.date,
+            origin=None,
+            path=b"A/B/C/b",
+        )
+    }
+
+    # Process R01 out of order (frontier in C should not be reused to guarantee that the
+    # first occurrence of A/B/C/b is in the CNT_EARLY_IN_REV relation)
+    revision_add(provenance, archive, [r01])
+
+    assert provenance.content_find_first(cnt_b_sha1) == ProvenanceResult(
+        content=cnt_b_sha1, revision=r01.id, date=r01.date, origin=None, path=b"A/B/C/b"
+    )
+    assert set(provenance.content_find_all(cnt_b_sha1)) == {
+        ProvenanceResult(
+            content=cnt_b_sha1,
+            revision=r01.id,
+            date=r01.date,
+            origin=None,
+            path=b"A/B/C/b",
+        ),
+        ProvenanceResult(
+            content=cnt_b_sha1,
+            revision=r02.id,
+            date=r02.date,
+            origin=None,
+            path=b"A/B/C/b",
+        ),
+    }