diff --git a/corelib/src/libs/SireIO/biosimspace.cpp b/corelib/src/libs/SireIO/biosimspace.cpp
index fa293afac..9f7dcbb18 100644
--- a/corelib/src/libs/SireIO/biosimspace.cpp
+++ b/corelib/src/libs/SireIO/biosimspace.cpp
@@ -466,7 +466,7 @@ namespace SireIO
             }
 
             // OPC
-            if (model == "OPC")
+            else if (model == "OPC")
             {
                 double a = 0.1477224;
 
@@ -592,7 +592,7 @@ namespace SireIO
             }
 
             // OPC
-            if (model == "OPC")
+            else if (model == "OPC")
             {
                 double a = 0.1477224;
 
diff --git a/corelib/src/libs/SireMaths/complex.cpp b/corelib/src/libs/SireMaths/complex.cpp
index ac24dbdfa..9701a81b4 100644
--- a/corelib/src/libs/SireMaths/complex.cpp
+++ b/corelib/src/libs/SireMaths/complex.cpp
@@ -396,7 +396,7 @@ namespace SireMaths
     /** Subtraction */
     Complex operator-(double x, const Complex &z)
     {
-        return z - x;
+        return Complex(x) - z;
     }
 
     /** Multiplication */
diff --git a/doc/source/changelog.rst b/doc/source/changelog.rst
index b01fafe49..a380a1f3c 100644
--- a/doc/source/changelog.rst
+++ b/doc/source/changelog.rst
@@ -52,6 +52,11 @@ organisation on `GitHub <https://github.com/openbiosim/sire>`__.
   propagate several independent trajectories by swapping the energy trajectory and
   simulation clock between blocks.
 
+* Fixed the ``double - Complex`` subtraction operator in ``SireMaths::Complex``.
+
+* Fixed a dangling ``else`` statement that caused ``setAmberWater`` and
+  ``setGromacsWater`` to fail when using the TIP4P water model.
+
 `2026.1.0 <https://github.com/openbiosim/sire/compare/2025.4.0...2026.1.0>`__ - June 2026
 -----------------------------------------------------------------------------------------