diff --git a/exercises/practice/hamming/.docs/instructions.md b/exercises/practice/hamming/.docs/instructions.md
index 020fdd0..b9ae6ef 100644
--- a/exercises/practice/hamming/.docs/instructions.md
+++ b/exercises/practice/hamming/.docs/instructions.md
@@ -1,6 +1,6 @@
 # Instructions
 
-Calculate the Hamming Distance between two DNA strands.
+Calculate the Hamming distance between two DNA strands.
 
 Your body is made up of cells that contain DNA.
 Those cells regularly wear out and need replacing, which they achieve by dividing into daughter cells.
@@ -9,18 +9,18 @@ In fact, the average human body experiences about 10 quadrillion cell divisions
 When cells divide, their DNA replicates too.
 Sometimes during this process mistakes happen and single pieces of DNA get encoded with the incorrect information.
 If we compare two strands of DNA and count the differences between them we can see how many mistakes occurred.
-This is known as the "Hamming Distance".
+This is known as the "Hamming distance".
 
-We read DNA using the letters C,A,G and T.
+We read DNA using the letters C, A, G and T.
 Two strands might look like this:
 
     GAGCCTACTAACGGGAT
     CATCGTAATGACGGCCT
     ^ ^ ^  ^ ^    ^^
 
-They have 7 differences, and therefore the Hamming Distance is 7.
+They have 7 differences, and therefore the Hamming distance is 7.
 
-The Hamming Distance is useful for lots of things in science, not just biology, so it's a nice phrase to be familiar with :)
+The Hamming distance is useful for lots of things in science, not just biology, so it's a nice phrase to be familiar with :)
 
 ## Implementation notes
 
diff --git a/exercises/practice/luhn/.docs/instructions.md b/exercises/practice/luhn/.docs/instructions.md
index 8cbe791..49934c1 100644
--- a/exercises/practice/luhn/.docs/instructions.md
+++ b/exercises/practice/luhn/.docs/instructions.md
@@ -22,7 +22,8 @@ The first step of the Luhn algorithm is to double every second digit, starting f
 We will be doubling
 
 ```text
-4_3_ 3_9_ 0_4_ 6_6_
+4539 3195 0343 6467
+↑ ↑  ↑ ↑  ↑ ↑  ↑ ↑  (double these)
 ```
 
 If doubling the number results in a number greater than 9 then subtract 9 from the product.
diff --git a/exercises/practice/protein-translation/.meta/tests.toml b/exercises/practice/protein-translation/.meta/tests.toml
index 5fb1890..b465aed 100644
--- a/exercises/practice/protein-translation/.meta/tests.toml
+++ b/exercises/practice/protein-translation/.meta/tests.toml
@@ -87,11 +87,15 @@ description = "Translation stops if STOP codon in middle of three-codon sequence
 [2c2a2a60-401f-4a80-b977-e0715b23b93d]
 description = "Translation stops if STOP codon in middle of six-codon sequence"
 
+[f6f92714-769f-4187-9524-e353e8a41a80]
+description = "Sequence of two non-STOP codons does not translate to a STOP codon"
+
 [1e75ea2a-f907-4994-ae5c-118632a1cb0f]
 description = "Non-existing codon can't translate"
 
 [9eac93f3-627a-4c90-8653-6d0a0595bc6f]
 description = "Unknown amino acids, not part of a codon, can't translate"
+reimplements = "1e75ea2a-f907-4994-ae5c-118632a1cb0f"
 
 [9d73899f-e68e-4291-b1e2-7bf87c00f024]
 description = "Incomplete RNA sequence can't translate"
diff --git a/exercises/practice/protein-translation/protein-translation.spec.wren b/exercises/practice/protein-translation/protein-translation.spec.wren
index 555c6b6..6157e4e 100644
--- a/exercises/practice/protein-translation/protein-translation.spec.wren
+++ b/exercises/practice/protein-translation/protein-translation.spec.wren
@@ -71,6 +71,13 @@ Testie.test("ProteinTranslation") { |do, skip|
         "Tyrosine",
       ])
     }
+
+    skip.test("Sequence of two non-STOP codons does not translate to a STOP codon") {
+      Expect.value(Tools.translate("AUGAUG")).toEqual([
+        "Methionine",
+        "Methionine"
+      ])
+    }
   }
 
   do.describe("Unexpected strands") {