diff --git a/src/snps/io/reader.py b/src/snps/io/reader.py
index 24ace60..34d9e4c 100644
--- a/src/snps/io/reader.py
+++ b/src/snps/io/reader.py
@@ -1505,7 +1505,7 @@ def parse(sep):
                         compression=compression,
                     )
                     df["chrom"] = df["chrom"].map(CHROMOSOME_FGA)
-            return (df,)
+            return (df, False, 38)  # incorrectly detects build as 37
 
         return self.read_helper("fga", parser)