diff --git a/Core/Parser/XmlAttributeState.cs b/Core/Parser/XmlAttributeState.cs
index 6c403d4..094428e 100644
--- a/Core/Parser/XmlAttributeState.cs
+++ b/Core/Parser/XmlAttributeState.cs
@@ -136,6 +136,10 @@ public XmlAttributeState (
 				var att = (XAttribute)context.Nodes.Pop ();
 				att.End (context.PositionBeforeCurrentChar);
 
+				if (!att.IsNamed) {
+					return Parent;
+				}
+
 				var element = (IAttributedXObject)context.Nodes.Peek ();
 
 				if (logDuplicate && context.Diagnostics is not null && element.Attributes.Get (att.Name, false) is not null) {
diff --git a/Core/Parser/XmlParser.cs b/Core/Parser/XmlParser.cs
index bf22845..7cc2f8a 100644
--- a/Core/Parser/XmlParser.cs
+++ b/Core/Parser/XmlParser.cs
@@ -141,7 +141,7 @@ public void Push (char c)
 			if (Context.Nodes.Count != 1 || Context.Nodes.Pop () is not XDocument doc) {
 				throw new InvalidParserStateException ("Malformed state stack when ending all nodes");
 			}
-			doc.End (Context.Position);
+			doc.End (Context.PositionBeforeCurrentChar);
 
 			for (int i = nodes.Length - 1; i >= 0; i--) {
 				var node = nodes[i];
diff --git a/Core/Parser/XmlParserContext.cs b/Core/Parser/XmlParserContext.cs
index 2ce663f..499aff4 100644
--- a/Core/Parser/XmlParserContext.cs
+++ b/Core/Parser/XmlParserContext.cs
@@ -61,8 +61,10 @@ public XmlParserContext (XmlParserState? previousState, XmlParserState currentSt
 
 		internal bool IsAtEndOfFile { get; set; }
 
-		internal int PositionBeforeCurrentChar => Position;
-		internal int PositionAfterCurrentChar => IsAtEndOfFile ? Position : Position + 1;
+		// during EOF, the position is after the last char, so these helpers ensure we don't end up with an invalid span
+		internal int PositionBeforeCurrentChar => IsAtEndOfFile? Position - 1 : Position;
+		internal int PositionAfterCurrentChar => IsAtEndOfFile ? Position - 1 : Position + 1;
+
 		internal TextSpan CurrentStateSpanIncludingCurrentChar => TextSpan.FromBounds(Position - CurrentStateLength, PositionAfterCurrentChar);
 		internal TextSpan CurrentStateSpanExcludingCurrentChar => TextSpan.FromBounds(Position - CurrentStateLength, PositionBeforeCurrentChar);
 
diff --git a/Core/Parser/XmlTagState.cs b/Core/Parser/XmlTagState.cs
index 1c121b9..831e0ea 100644
--- a/Core/Parser/XmlTagState.cs
+++ b/Core/Parser/XmlTagState.cs
@@ -68,7 +68,11 @@ public XmlTagState (XmlAttributeState attributeState, XmlNameState nameState)
 
 			// if the current node on the stack is ended or not an element, then it's the parent
 			// and we need to create the new element
-			if ((element is null || (element.IsEnded && !isEndOfFile))) {
+			if (isEndOfFile) {
+				if (element is null) {
+					throw new InvalidParserStateException ("When entering tag state during EOF, there must be an XElement on the stack");
+				}
+			} else if (element is null || element.IsEnded) {
 				var parent = peekedNode;
 				element = new XElement (context.Position - STARTOFFSET) { Parent = parent };
 				context.Nodes.Push (element);
@@ -78,14 +82,16 @@ public XmlTagState (XmlAttributeState attributeState, XmlNameState nameState)
 			}
 
 			if (isEndOfFile || c == '<') {
-				element.End (context.PositionBeforeCurrentChar);
+				if (!element.IsEnded) {
+					element.End (context.PositionBeforeCurrentChar);
+				}
 				if (isEndOfFile) {
 					context.Diagnostics?.Add (XmlCoreDiagnostics.IncompleteTagEof, context.PositionBeforeCurrentChar);
 				}
 				else if (element.Name.IsValid) {
 					context.Diagnostics?.Add (XmlCoreDiagnostics.MalformedNamedTag, context.PositionBeforeCurrentChar, element.Name.FullName, '<');
 				} else {
-					context.Diagnostics?.Add (XmlCoreDiagnostics.UnnamedTag, context.Position);
+					context.Diagnostics?.Add (XmlCoreDiagnostics.UnnamedTag, context.PositionBeforeCurrentChar);
 				}
 
 				if (isEndOfFile) {