diff --git a/mdformat_mkdocs/plugin.py b/mdformat_mkdocs/plugin.py
index e3a935e..c13fe4f 100644
--- a/mdformat_mkdocs/plugin.py
+++ b/mdformat_mkdocs/plugin.py
@@ -128,9 +128,19 @@ def __init__(self) -> None:
         self._lookup: dict[str, int] = {}
 
     def _get_block_indent(self, indent: str, content: str) -> str:
+        if (
+            self._block_type == "marked"
+            and content
+            and len(indent) <= len(self._block_indent)
+        ):
+            # Remove tracked indent on end of a marked (content tab or admonition) block
+            # `Which could be the start of a new block, so this must be first
+            self._block_type = None
+            self._block_indent = ""
+
         if self._block_type is None:
             # Identify block type
-            markers = CONTENT_TAB_MARKERS + MKDOCS_ADMON_MARKERS
+            markers = CONTENT_TAB_MARKERS.union(MKDOCS_ADMON_MARKERS)
             if content.startswith("```"):
                 self._block_type = "code"
             elif any(content.startswith(f"{marker} ") for marker in markers):
@@ -142,14 +152,6 @@ def _get_block_indent(self, indent: str, content: str) -> str:
             # Remove tracked indent on end of code block
             self._block_type = None
             self._block_indent = ""
-        elif (
-            self._block_type == "marked"
-            and content
-            and len(indent) <= len(self._block_indent)
-        ):
-            # Remove tracked indent on end of a marked (content tab or admonition) block
-            self._block_type = None
-            self._block_indent = ""
 
         return self._block_indent
 
diff --git a/tests/format/fixtures.md b/tests/format/fixtures.md
index bd11ebb..ba1870f 100644
--- a/tests/format/fixtures.md
+++ b/tests/format/fixtures.md
@@ -1269,3 +1269,73 @@ Example with '===+' (active) from <https://facelessuser.github.io/pymdown-extens
 === "Not Me Either"
     Another Tab
 .
+
+
+More complex example to validate formatting when nested
+.
+1. List Outer
+
+    ???+ Note
+    
+        === "First"
+    
+             Markdown **content**.
+    
+             Multiple paragraphs.
+        
+            ??? "Second"
+        
+                 Markdown **content**.
+        
+                 Multiple paragraphs.
+        
+                ===+ "Third"
+            
+                     - List Item
+            
+                     - Another Item
+        
+                        === "Fourth"
+                    
+                             - List Item
+                    
+                             - Another Item
+        
+                        ===! "Lastly a new item"
+    
+                            Markdown **content** for last item.
+    
+                            Very last indented paragraph.
+
+2. Next
+.
+1. List Outer
+
+    ???+ Note
+        === "First"
+            Markdown **content**.
+
+            Multiple paragraphs.
+
+            ??? "Second"
+                Markdown **content**.
+
+                Multiple paragraphs.
+
+                ===+ "Third"
+                    - List Item
+
+                    - Another Item
+
+                        === "Fourth"
+                            - List Item
+
+                            - Another Item
+
+                        ===! "Lastly a new item"
+                            Markdown **content** for last item.
+
+                            Very last indented paragraph.
+
+1. Next
+.