diff --git a/src/random.cpp b/src/random.cpp
--- a/src/random.cpp
+++ b/src/random.cpp
@@ -403,6 +403,9 @@
 }
 
 std::vector<uint8_t> FastRandomContext::randbytes(size_t len) {
+    if (requires_seed) {
+        RandomSeed();
+    }
     std::vector<uint8_t> ret(len);
     if (len > 0) {
         rng.Output(&ret[0], len);
diff --git a/src/test/random_tests.cpp b/src/test/random_tests.cpp
--- a/src/test/random_tests.cpp
+++ b/src/test/random_tests.cpp
@@ -36,12 +36,19 @@
     BOOST_CHECK(ctx1.randbytes(50) == ctx2.randbytes(50));
 
     // Check that a nondeterministic ones are not
-    FastRandomContext ctx3;
-    FastRandomContext ctx4;
-    // extremely unlikely to be equal
-    BOOST_CHECK(ctx3.rand64() != ctx4.rand64());
-    BOOST_CHECK(ctx3.rand256() != ctx4.rand256());
-    BOOST_CHECK(ctx3.randbytes(7) != ctx4.randbytes(7));
+    {
+        FastRandomContext ctx3, ctx4;
+        // extremely unlikely to be equal
+        BOOST_CHECK(ctx3.rand64() != ctx4.rand64());
+    }
+    {
+        FastRandomContext ctx3, ctx4;
+        BOOST_CHECK(ctx3.rand256() != ctx4.rand256());
+    }
+    {
+        FastRandomContext ctx3, ctx4;
+        BOOST_CHECK(ctx3.randbytes(7) != ctx4.randbytes(7));
+    }
 }
 
 BOOST_AUTO_TEST_CASE(fastrandom_randbits) {