diff --git a/core/modules/parsers/parseutils.js b/core/modules/parsers/parseutils.js
index c284be3bab..250a82baed 100644
--- a/core/modules/parsers/parseutils.js
+++ b/core/modules/parsers/parseutils.js
@@ -287,7 +287,7 @@ exports.parseMacroParameterAsAttribute = function(source,pos) {
 	var nameToken = $tw.utils.parseTokenRegExp(source,pos,reAttributeName),
 		namePos = nameToken && $tw.utils.skipWhiteSpace(source,nameToken.end),
 		separatorToken = nameToken && $tw.utils.parseTokenRegExp(source,namePos,/=|:/g),
-		isNewStyleSeparator = true; // If there is no separator then we allow new style values
+		isNewStyleSeparator = false; // If there is no separator then we don't allow new style values
 	// If we have a name and a separator then we have a named attribute
 	if(nameToken && separatorToken) {
 		node.name = nameToken.match[1];
diff --git a/editions/test/tiddlers/tests/data/macros/dynamic-macros/Attribute.tid b/editions/test/tiddlers/tests/data/macros/dynamic-macros/Attribute.tid
index d6276707bc..2d7313861e 100644
--- a/editions/test/tiddlers/tests/data/macros/dynamic-macros/Attribute.tid
+++ b/editions/test/tiddlers/tests/data/macros/dynamic-macros/Attribute.tid
@@ -13,10 +13,6 @@ It is $param$
 -
 <$text text=<<mamacromamacro param={{{ [[a]addprefix[b]] }}}>>/>
 -
-<$text text=<<mamacromamacro param={{{ [[b]addprefix[a]] }}}>>/>
--
-<$text text=<<mamacromamacro {{{ [[b]addprefix[a]] }}}>>/>
--
 <$text text=<<mamacromamacro param>>/>
 
 +
@@ -26,9 +22,5 @@ title: ExpectedResult
 -
 It is ba
 -
-It is ab
--
-It is ab
--
 It is param
 </p>
\ No newline at end of file
diff --git a/editions/test/tiddlers/tests/data/macros/dynamic-macros/Standalone.tid b/editions/test/tiddlers/tests/data/macros/dynamic-macros/Standalone.tid
index 2da5555b30..bdce9484d5 100644
--- a/editions/test/tiddlers/tests/data/macros/dynamic-macros/Standalone.tid
+++ b/editions/test/tiddlers/tests/data/macros/dynamic-macros/Standalone.tid
@@ -15,10 +15,9 @@ It is $one$ and $two$ or <<__one__>> and <<__two__>>.
 
 <<mamacro one={{{ [[b]addprefix[a]] }}}>>
 
-<<mamacro {{{ [[b]addprefix[a]] }}}>>
 
 <<mamacro one>>
 +
 title: ExpectedResult
 
-<p>It is red and green or red and green.</p><p>It is ab and green or ab and green.</p><p>It is ab and green or ab and green.</p><p>It is one and green or one and green.</p>
\ No newline at end of file
+<p>It is red and green or red and green.</p><p>It is ab and green or ab and green.</p><p>It is one and green or one and green.</p>
\ No newline at end of file