Selenium IDE - Assert commands returning false negatives

If I run IDE scripts containing assert commands those steps pass when they should not.

If those same steps are executed individually (i.e. selected in the steps pane and then x is pressed) they fail as expected.

If I run those same scripts with the assert commands replaced with verify commands then the steps fail as expected.

I am using Selenium IDE 2.9.1, Firefox 50.0.1, macOS 10.12.3

See attached screenshot and source below.

Selenium results

Source:

<tr>
        <td>open</td>
        <td>http://ift.tt/2mwo9T5;
        <td></td>
</tr>
<tr>
        <td>waitForText</td>
        <td>//h3/span</td>
        <td>Selenium IDE</td>
</tr>
<tr>
        <td>verifyText</td>
        <td>//h3/span</td>
        <td>wookie</td>
</tr>
<tr>
        <td>verifyText</td>
        <td>//h3/span</td>
        <td>Selenium IDE</td>
</tr>
<tr>
        <td>verifyNotText</td>
        <td>//h3/span</td>
        <td>Selenium IDE</td>
</tr>
<tr>
        <td>verifyNotVisible</td>
        <td>//h3/span</td>
        <td>Selenium IDE</td>
</tr>
<tr>
        <td>verifyVisible</td>
        <td>//h3/span</td>
        <td>Selenium IDE</td>
</tr>
<tr>
        <td>verifyEval</td>
        <td>storedVars['model1']==storedVars['emailConfirm1']</td>
        <td>true</td>
</tr>
<tr>
        <td>verifyLocation</td>
        <td>http://ift.tt/2mYl2Q2;
        <td></td>
</tr>
<tr>
        <td>assertText</td>
        <td>//h3/span</td>
        <td>wookie</td>
</tr>
<tr>
        <td>assertText</td>
        <td>//h3/span</td>
        <td>Selenium IDE</td>
</tr>
<tr>
        <td>assertNotText</td>
        <td>//h3/span</td>
        <td>Selenium IDE</td>
</tr>
<tr>
        <td>assertNotVisible</td>
        <td>//h3/span</td>
        <td>Selenium IDE</td>
</tr>
<tr>
        <td>assertVisible</td>
        <td>//h3/span</td>
        <td>Selenium IDE</td>
</tr>
<tr>
        <td>assertEval</td>
        <td>storedVars['model1']==storedVars['emailConfirm1']</td>
        <td>true</td>
</tr>
<tr>
        <td>assertLocation</td>
        <td>http://ift.tt/2mYl2Q2;
        <td></td>
</tr>
<tr>
        <td>verifyEval</td>
        <td>storedVars['model1']==storedVars['emailConfirm1']</td>
        <td>true</td>
</tr>