diff --git a/Makefile b/Makefile
index a056904..19cda13 100644
--- a/Makefile
+++ b/Makefile
@@ -62,6 +62,7 @@ checkmodel/%: src/%.yaml
 	@linkml-lint \
 		--config .linkmllint.yaml \
 		--max-warnings 0 \
+		--validate \
 		$<
 # generate various output formats, they all have the potential to
 # reveal "hidden" issues
diff --git a/src/distribution/unreleased.yaml b/src/distribution/unreleased.yaml
index d37bb31..cf8f76e 100644
--- a/src/distribution/unreleased.yaml
+++ b/src/distribution/unreleased.yaml
@@ -126,9 +126,10 @@ types:
     uri: xsd:nonNegativeInteger
     base: int
     description: An integer
-    notes: >-
-      Integer with minimum (inclusive) value of zero, i.e. the standard
-      mathematical concept of the non-negative integers.
+    notes:
+      - >-
+        Integer with minimum (inclusive) value of zero, i.e. the standard
+        mathematical concept of the non-negative integers.
     broad_mappings:
       - schema:Integer
 
diff --git a/src/prov/unreleased.yaml b/src/prov/unreleased.yaml
index 289000c..0d3a487 100644
--- a/src/prov/unreleased.yaml
+++ b/src/prov/unreleased.yaml
@@ -95,7 +95,8 @@ types:
       where TZD is the time zone designator (Z or +hh:mm or -hh:mm)
     typeof: string
     pattern: '^(\d{4})|(\d{4}-[01]\d)|(\d{4}-[01]\d-[0-3]\d)|(\d{4}-[01]\d-[0-3]\dT[0-2]\d:[0-5]\d:[0-5]\d\.\d+([+-][0-2]\d:[0-5]\d|Z))|(\d{4}-[01]\d-[0-3]\dT[0-2]\d:[0-5]\d:[0-5]\d([+-][0-2]\d:[0-5]\d|Z))|(\d{4}-[01]\d-[0-3]\dT[0-2]\d:[0-5]\d([+-][0-2]\d:[0-5]\d|Z))$'
-    see_also: https://www.w3.org/TR/NOTE-datetime
+    see_also:
+      - https://www.w3.org/TR/NOTE-datetime
 
 
 slots:
diff --git a/src/thing/unreleased.yaml b/src/thing/unreleased.yaml
index 02f269b..ee78385 100644
--- a/src/thing/unreleased.yaml
+++ b/src/thing/unreleased.yaml
@@ -307,8 +307,10 @@ classes:
     slot_usage:
       value:
         required: true
-        notes: >-
-          It is required, because when it is not needed, `Thing` should be
-          used as a type. Its absence is therefore likely a sign of an error.
+        notes:
+          - >-
+            It is required, because when it is not needed, `Thing` should
+            be used as a type. Its absence is therefore likely a sign of
+            an error.
     exact_mappings:
       - obo:OBI_0001933