diff --git a/nml/actions/action2var.py b/nml/actions/action2var.py
index 878a789..6dd607e 100644
--- a/nml/actions/action2var.py
+++ b/nml/actions/action2var.py
@@ -619,6 +619,9 @@ class Varaction2Parser:
             self.var_list.append(expr)
             self.var_list_size += expr.get_size()
 
+        elif isinstance(expr, expression.SpriteGroupRef):
+            self.parse_proc_call(expr)
+
         else:
             expr.supported_by_action2(True)
             assert False #supported_by_action2 should have raised the correct error already
diff --git a/regression/019_switch.nml b/regression/019_switch.nml
index 3e3806c..542ec32 100644
--- a/regression/019_switch.nml
+++ b/regression/019_switch.nml
@@ -13,7 +13,7 @@ switch(FEAT_INDUSTRIES, SELF, return_switch, STORE_PERM(current_year - 1950, 0x0
 /* store a value of 4 into the permanent register 0x00, but evaluate current_month
  * use the array notation
  */
-switch(FEAT_INDUSTRIES, SELF, coal_mine_subtype_switch, [STORE_PERM(4, 0x00), current_month]) {
+switch(FEAT_INDUSTRIES, SELF, coal_mine_subtype_switch, [STORE_PERM(4, 0x00), return_switch, current_month]) {
     0..10: return string(STR_COALMINE_MONTH_0_10);
     13: return_switch; // unreachable
     return string(STR_COALMINE_MONTH_11);