diff --git a/src/main/java/net/fabricmc/mappingio/format/tiny/Tiny1FileReader.java b/src/main/java/net/fabricmc/mappingio/format/tiny/Tiny1FileReader.java
index 77986efc..9d807b6d 100644
--- a/src/main/java/net/fabricmc/mappingio/format/tiny/Tiny1FileReader.java
+++ b/src/main/java/net/fabricmc/mappingio/format/tiny/Tiny1FileReader.java
@@ -153,6 +153,7 @@ private static void read(ColumnFileReader reader, MappingVisitor visitor) throws
 							StandardProperty property = StandardProperties.getByName(key);
 
 							if (property != null) {
+								if (!property.isApplicableTo(format)) continue; // How did it get there?
 								key = property.getId();
 							}
 
diff --git a/src/main/java/net/fabricmc/mappingio/format/tiny/Tiny2FileReader.java b/src/main/java/net/fabricmc/mappingio/format/tiny/Tiny2FileReader.java
index b4a7b184..7c174ea1 100644
--- a/src/main/java/net/fabricmc/mappingio/format/tiny/Tiny2FileReader.java
+++ b/src/main/java/net/fabricmc/mappingio/format/tiny/Tiny2FileReader.java
@@ -102,6 +102,7 @@ private static void read(ColumnFileReader reader, MappingVisitor visitor) throws
 						StandardProperty property = StandardProperties.getByName(key);
 
 						if (property != null) {
+							if (!property.isApplicableTo(format)) continue; // How did it get there?
 							key = property.getId();
 
 							if (property == StandardProperties.ESCAPED_NAMES) {