diff --git a/bin/compose-core b/bin/compose-core
index 7ff4446..b8dcc30 100755
--- a/bin/compose-core
+++ b/bin/compose-core
@@ -2069,7 +2069,7 @@ export -f get_service_relations
 
 
 get_service_relation() {
-    local service="$1" relation="$2" cache_file="$state_tmpdir/$FUNCNAME.cache.$1" \
+    local service="$1" relation="$2" cache_file="$state_tmpdir/$FUNCNAME.cache.$1.$2" \
           rn ts rc td
     if [ -e "$cache_file" ]; then
         #debug "$FUNCNAME: SESSION cache hit $1"