diff --git a/src/_pytest/_io/terminalwriter.py b/src/_pytest/_io/terminalwriter.py
index 4b8219c0d..1b11539db 100644
--- a/src/_pytest/_io/terminalwriter.py
+++ b/src/_pytest/_io/terminalwriter.py
@@ -225,6 +225,10 @@ class TerminalWriter:
                 )
                 if highlighted[-1] == "\n" and source[-1] != "\n":
                     highlighted = highlighted[:-1]
+
+                # Some lexers will not set the initial color explicitly
+                # which may lead to the previous color being propagated to the
+                # start of the expression
                 return "\x1b[0m" + highlighted
             except pygments.util.ClassNotFound:
                 raise UsageError(