diff --git a/make/RunTests.gmk b/make/RunTests.gmk
index 95d3dee70139c..51c75cc487203 100644
--- a/make/RunTests.gmk
+++ b/make/RunTests.gmk
@@ -583,6 +583,8 @@ define SetMicroValue
   else
     ifneq ($3, )
       $1_$2 := $3
+    else
+      $1_$2 :=
     endif
   endif
 endef
@@ -709,6 +711,8 @@ define SetJtregValue
     else
       ifneq ($3, )
         $1_$2 := $3
+      else
+        $1_$2 :=
       endif
     endif
   endif
@@ -841,6 +845,12 @@ define SetupRunJtregTestBody
     endif
   endif
 
+  ifeq ($$(JTREG_RUN_PROBLEM_LISTS), true)
+    JTREG_PROBLEM_LIST_PREFIX := -match:
+  else
+    JTREG_PROBLEM_LIST_PREFIX := -exclude:
+  endif
+
   ifneq ($$(JTREG_TEST_THREAD_FACTORY), )
     $1_JTREG_BASIC_OPTIONS += -testThreadFactoryPath:$$(JTREG_TEST_THREAD_FACTORY_JAR)
     $1_JTREG_BASIC_OPTIONS += -testThreadFactory:$$(JTREG_TEST_THREAD_FACTORY)
@@ -869,7 +879,7 @@ define SetupRunJtregTestBody
   # version of the JDK.
   $1_JTREG_BASIC_OPTIONS += -$$($1_JTREG_TEST_MODE) \
       -verbose:$$(JTREG_VERBOSE) -retain:$$(JTREG_RETAIN) \
-      -concurrency:$$($1_JTREG_JOBS) -timeoutFactor:$$(JTREG_TIMEOUT_FACTOR) \
+      -concurrency:$$($1_JTREG_JOBS) \
       -vmoption:-XX:MaxRAMPercentage=$$($1_JTREG_MAX_RAM_PERCENTAGE) \
       -vmoption:-Dtest.boot.jdk="$$(BOOT_JDK)" \
       -vmoption:-Djava.io.tmpdir="$$($1_TEST_TMP_DIR)"
@@ -902,12 +912,6 @@ define SetupRunJtregTestBody
     $1_JTREG_BASIC_OPTIONS += -nativepath:$$($1_JTREG_NATIVEPATH)
   endif
 
-  ifeq ($$(JTREG_RUN_PROBLEM_LISTS), true)
-    JTREG_PROBLEM_LIST_PREFIX := -match:
-  else
-    JTREG_PROBLEM_LIST_PREFIX := -exclude:
-  endif
-
   ifneq ($$($1_JTREG_PROBLEM_LIST), )
     $1_JTREG_BASIC_OPTIONS += $$(addprefix $$(JTREG_PROBLEM_LIST_PREFIX), $$($1_JTREG_PROBLEM_LIST))
   endif
@@ -994,6 +998,7 @@ define SetupRunJtregTestBody
   endif
 
   JTREG_TIMEOUT_FACTOR ?= $$(JTREG_AUTO_TIMEOUT_FACTOR)
+  $1_JTREG_BASIC_OPTIONS += -timeoutFactor:$$(JTREG_TIMEOUT_FACTOR)
 
   clean-outputdirs-$1:
 	$$(call LogWarn, Clean up dirs for $1)