diff --git a/doc/en/Authoring/Question_options.md b/doc/en/Authoring/Question_options.md
index ec105c234e..7eee340471 100644
--- a/doc/en/Authoring/Question_options.md
+++ b/doc/en/Authoring/Question_options.md
@@ -91,16 +91,27 @@ This option sets the value of [Maxima](../CAS/Maxima_background.md)'s
 
     sqrtdispflag
 
-When false the prefix function `sqrt(x)` will be displayed as \(x^{1/2}\).
-Please note that Maxima (by default) does not like to use the \(\sqrt{}\) symbol.
-The internal representation favours fractional powers, for very good reasons.
-In  Maxima 5.19.1 we get:
+When false the prefix function `sqrt(x)` will be displayed as \(x^{1/2}\).  This setting is _global_ to the question, and having both notations co-exist in one question is very tricky.  You need to have `simp:false` throughout the question.
+
+By default Maxima does not like to use the \(\sqrt{}\) symbol. The internal representation favours fractional powers, for very good reasons. In  Maxima we get:
 
     (%i1) 4*sqrt(2);
     (%o1) 2^(5/2)
     (%i2) 6*sqrt(2);
     (%o2) 3*2^(3/2)
 
+Furthermore, if you execute this in a Maxima session
+
+    simp:true;
+    p:1+sqrt(x);
+    ?print(p);
+
+Then the displayed value of `p` is \(\sqrt{x}+1\) whereas the internal representation of `p` is
+
+    ((MPLUS SIMP) 1 ((MEXPT SIMP) $X ((RAT SIMP) 1 2))) 
+
+This means that internally Maxima has converted `sqrt(x)` to `x^(1/2)`, even though it is by default displayed as `sqrt`.  This is an example where the displayed form (text and LaTeX) does not match Maxima's internal representation.
+
 Do you really want to continue using \(\sqrt{}\) in your teaching?  In his *Elements of Algebra*, L. Euler wrote the following.
 
 > \(\S 200\) We may therefore entirely reject the radical signs at present made use of, and employ in their stead
diff --git a/tests/castext_test.php b/tests/castext_test.php
index 404a5e4373..21abf911c3 100644
--- a/tests/castext_test.php
+++ b/tests/castext_test.php
@@ -2546,4 +2546,73 @@ public function test_format_moodle_parsons() {
         $expected = $txt;
         $this->assertEquals($expected, $at1->get_rendered());
     }
+
+    /**
+     * @covers \qtype_stack\stack_cas_castext2_latex
+     * @covers \qtype_stack\stack_cas_keyval
+     */
+    public function test_sqrtdispflag() {
+        // Test 1.
+        $a2 = ['p1:1+sqrt(x)'];
+        $s2 = [];
+        foreach ($a2 as $s) {
+            $cs = stack_ast_container::make_from_teacher_source($s, '', new stack_cas_security(), []);
+            $this->assertTrue($cs->get_valid());
+            $s2[] = $cs;
+        }
+        $options = new stack_options();
+        $options->set_option('simplify', true);
+        $cs2 = new stack_cas_session2($s2, $options, 7);
+
+        $txtinput = '{@p1@}, {@(sqrtdispflag:false,p1)@}, {@p1@}';
+        // Notice the 3rd expression is still using ^(1/2) because the sqrtdispflag:false becomes global.
+        $expected = '\({\sqrt{x}+1}\), \({x^{\frac{1}{2}}+1}\), \({x^{\frac{1}{2}}+1}\)';
+        $at1 = castext2_evaluatable::make_from_source($txtinput, 'test-case');
+        $this->assertTrue($at1->get_valid());
+        $cs2->add_statement($at1);
+        $cs2->instantiate();
+        $this->assertEquals($expected, $at1->get_rendered());
+
+        // Test 2.
+        $a2 = ['p1:1+sqrt(x)'];
+        $s2 = [];
+        foreach ($a2 as $s) {
+            $cs = stack_ast_container::make_from_teacher_source($s, '', new stack_cas_security(), []);
+            $this->assertTrue($cs->get_valid());
+            $s2[] = $cs;
+        }
+        $options = new stack_options();
+        $options->set_option('simplify', true);
+        $cs2 = new stack_cas_session2($s2, $options, 7);
+        
+        $txtinput = '{@p1@}, {@block([sqrtdispflag],sqrtdispflag:false,p1)@}, {@p1@}';
+        // None of the expressions use ^(1/2) because the sqrtdispflag:false is a local variable.
+        $expected = '\({\sqrt{x}+1}\), \({\sqrt{x}+1}\), \({\sqrt{x}+1}\)';
+        $at1 = castext2_evaluatable::make_from_source($txtinput, 'test-case');
+        $this->assertTrue($at1->get_valid());
+        $cs2->add_statement($at1);
+        $cs2->instantiate();
+        $this->assertEquals($expected, $at1->get_rendered());
+
+        // Test 3.
+        $a2 = ['p1:1+sqrt(x)'];
+        $s2 = [];
+        foreach ($a2 as $s) {
+            $cs = stack_ast_container::make_from_teacher_source($s, '', new stack_cas_security(), []);
+            $this->assertTrue($cs->get_valid());
+            $s2[] = $cs;
+        }
+        $options = new stack_options();
+        $options->set_option('simplify', true);
+        $cs2 = new stack_cas_session2($s2, $options, 7);
+
+        $txtinput = '{@p1@}, {@(sqrtdispflag:false,p1)@}, {@(sqrtdispflag:true,p1)@}';
+        // Need to explicitly switch back in the _next_ expresion. Akward.
+        $expected = '\({\sqrt{x}+1}\), \({x^{\frac{1}{2}}+1}\), \({\sqrt{x}+1}\)';
+        $at1 = castext2_evaluatable::make_from_source($txtinput, 'test-case');
+        $this->assertTrue($at1->get_valid());
+        $cs2->add_statement($at1);
+        $cs2->instantiate();
+        $this->assertEquals($expected, $at1->get_rendered());
+    }
 }