diff --git a/LOG b/LOG
index 64c1cf99a3..cf0db40a3f 100644
--- a/LOG
+++ b/LOG
@@ -576,3 +576,9 @@
   added a batch script for locating Visual Studio's vcredist merge
   modules, updated installer paths and names.
     wininstall/*
+- fixed np-normalize-context pass to process trivs list in mvset forms
+  in tail and predicate context and added regression tests.  Thanks to
+  @marcomaggi for reporting the bug and @yjqww6 for providing a
+  simplified test and finding the initial solution.
+    cpnanopass.ss,
+    3.ms
diff --git a/mats/3.ms b/mats/3.ms
index ab1e794204..2410d66d9e 100644
--- a/mats/3.ms
+++ b/mats/3.ms
@@ -2049,6 +2049,26 @@
     (let ()
       (import $mrvs-double-call)
       (double-call 'a)))
+
+  ; regression testing for handling mvset in tail context
+  (call-with-values
+    (lambda ()
+      (call-with-values
+        (lambda ()
+          (+ (random 1) 7))
+        list))
+    (lambda l (equal? l '((7)))))
+
+  ; regression testing for handling mvset in predicate context
+  (if (call-with-values
+        (lambda ()
+          (call-with-values
+            (lambda ()
+              (+ (random 1) 7))
+            list))
+        (lambda l (equal? l '((7)))))
+      #t
+      #f)
 )
 
 (mat let-values
diff --git a/s/cpnanopass.ss b/s/cpnanopass.ss
index 3bd6777f06..9f23cb2e72 100644
--- a/s/cpnanopass.ss
+++ b/s/cpnanopass.ss
@@ -9756,7 +9756,7 @@
            (tail (mvcall ,info ,mdcl ,t0? ,t1 ... (,t* ...)))
            (true))]
         [(set! ,[lvalue] ,[rhs]) `(seq (set! ,lvalue ,rhs) (true))]
-        [(mvset ,info (,mdcl ,[t0?] ,[t1] ...) (,t* ...) ((,x** ...) ,interface* ,l*) ...)
+        [(mvset ,info (,mdcl ,[t0?] ,[t1] ...) (,[t*] ...) ((,x** ...) ,interface* ,l*) ...)
          `(seq
             (mvset ,info (,mdcl ,t0? ,t1 ...) (,t* ...) ((,x** ...) ,interface* ,l*) ...)
             (true))]
@@ -9826,7 +9826,7 @@
          (guard (info-call-error? info) (fx< (debug-level) 2))
          `(mvcall ,info ,mdcl ,t0? ,t1 ... (,t* ...))]
         [(set! ,[lvalue] ,[rhs]) `(seq (set! ,lvalue ,rhs) ,(%constant svoid))]
-        [(mvset ,info (,mdcl ,[t0?] ,[t1] ...) (,t* ...) ((,x** ...) ,interface* ,l*) ...)
+        [(mvset ,info (,mdcl ,[t0?] ,[t1] ...) (,[t*] ...) ((,x** ...) ,interface* ,l*) ...)
          `(seq
             (mvset ,info (,mdcl ,t0? ,t1 ...) (,t* ...) ((,x** ...) ,interface* ,l*) ...)
             ,(%constant svoid))]