diff --git a/tex/latex/biblatex/biblatex.sty b/tex/latex/biblatex/biblatex.sty
index e31f45eb6..a0727fd05 100644
--- a/tex/latex/biblatex/biblatex.sty
+++ b/tex/latex/biblatex/biblatex.sty
@@ -8153,7 +8153,7 @@
   \ifblank{#1}
     {\def\blx@tempa{default}}
     {\def\blx@tempa{#1}}%
-  \def\blx@tempb{#1}%
+  \def\blx@tempb{#2}%
   \ifcsundef{abx@field@\blx@tempb source}
     {}%
     {\letcs\blx@tempb{abx@field@\blx@tempb source}%