Office add-in validation fails for IconUrl though it is a 32x32 px image - ms-word

Question

I have the following line in my manifest
<IconUrl DefaultValue="images/icon-32.png"/>
and also
<Host ...>
...
<Control ...>
....
<Icon>
<bt:Image size="16" DefaultValue="images/icon-16.png"/>
<bt:Image size="32" DefaultValue="images/icon-32.png"/>
<bt:Image size="80" DefaultValue="images/icon-80.png"/>
</Icon>
</Control>
</Host>
But when I submit for approval, I am getting the following error from the Office Store Team.
The icon referenced in the IconUrl element of your add-in manifest must be 32x32 pixels in dimension.
And it is referred to the document Validation Policies point 5.10
I have verified the image to be exactly 32x32 px in size in PNG format. While testing the add-in, the icon-32.png is loaded in the Home menu panel
Update
The complete manifest file is added below
<?xml version="1.0" encoding="UTF-8"?>
<OfficeApp
xmlns="http://schemas.microsoft.com/office/appforoffice/1.1"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:bt="http://schemas.microsoft.com/office/officeappbasictypes/1.0"
xmlns:ov="http://schemas.microsoft.com/office/taskpaneappversionoverrides" xsi:type="TaskPaneApp">
<Id>aabbccdd-aabbccdd-aabbccdd-aabbccdd</Id>
<Version>1.0</Version>
<ProviderName>TestAddin</ProviderName>
<DefaultLocale>en-US</DefaultLocale>
<DisplayName DefaultValue="TestAddin" />
<Description DefaultValue="A Test addin"/>
<IconUrl DefaultValue="https://wireframepro.mockflow.com/integrations/office365/images/icon-32.png" />
<SupportUrl DefaultValue="http://tesaddin.local" />
<AppDomains>
<AppDomain>http://tesaddin.local/</AppDomain>
</AppDomains>
<Hosts>
<Host Name="Document" />
</Hosts>
<DefaultSettings>
<SourceLocation DefaultValue="http://tesaddin.local/index.html" />
</DefaultSettings>
<Permissions>ReadWriteDocument</Permissions>
<Requirements>
<Sets DefaultMinVersion="1.1">
<Set Name="WordApi" MinVersion="1.1"/>
</Sets>
</Requirements>
<VersionOverrides
xmlns="http://schemas.microsoft.com/office/taskpaneappversionoverrides" xsi:type="VersionOverridesV1_0">
<Hosts>
<Host xsi:type="Document">
<DesktopFormFactor>
<GetStarted>
<Title resid="ACME.GetStarted.Title"/>
<Description resid="ACME.GetStarted.Description"/>
<LearnMoreUrl resid="ACME.GetStarted.LearnMoreUrl"/>
</GetStarted>
<ExtensionPoint xsi:type="PrimaryCommandSurface">
<OfficeTab id="TabHome">
<Group id="ACME.Group1">
<Label resid="ACME.Group1Label" />
<Icon>
<bt:Image size="16" resid="ACME.tpicon_16x16" />
<bt:Image size="32" resid="ACME.tpicon_32x32" />
<bt:Image size="80" resid="ACME.tpicon_80x80" />
</Icon>
<Control xsi:type="Button" id="ACME.TaskpaneButton">
<Label resid="ACME.TaskpaneButton.Label" />
<Supertip>
<Title resid="ACME.TaskpaneButton.Label" />
<Description resid="ACME.TaskpaneButton.Tooltip" />
</Supertip>
<Icon>
<bt:Image size="16" resid="ACME.tpicon_16x16" />
<bt:Image size="32" resid="ACME.tpicon_32x32" />
<bt:Image size="80" resid="ACME.tpicon_80x80" />
</Icon>
<Action xsi:type="ShowTaskpane">
<TaskpaneId>ButtonId1</TaskpaneId>
<SourceLocation resid="ACME.Taskpane.Url" />
</Action>
</Control>
</Group>
</OfficeTab>
</ExtensionPoint>
</DesktopFormFactor>
</Host>
</Hosts>
<Resources>
<bt:Images>
<bt:Image id="ACME.tpicon_16x16" DefaultValue="https://wireframepro.mockflow.com/integrations/office365/images/icon-16.png" />
<bt:Image id="ACME.tpicon_32x32" DefaultValue="https://wireframepro.mockflow.com/integrations/office365/images/icon-32.png" />
<bt:Image id="ACME.tpicon_80x80" DefaultValue="https://wireframepro.mockflow.com/integrations/office365/images/icon-80.png" />
</bt:Images>
<bt:Urls>
<bt:Url id="ACME.Taskpane.Url" DefaultValue="http://tesaddin.local/index.html" />
<bt:Url id="ACME.GetStarted.LearnMoreUrl" DefaultValue="https://go.microsoft.com/fwlink/?LinkId=276812" />
</bt:Urls>
<bt:ShortStrings>
<bt:String id="ACME.TaskpaneButton.Label" DefaultValue="Open Editor" />
<bt:String id="ACME.Group1Label" DefaultValue="Test Addin" />
<bt:String id="ACME.GetStarted.Title" DefaultValue="Get started with Test Addin" />
</bt:ShortStrings>
<bt:LongStrings>
<bt:String id="ACME.TaskpaneButton.Tooltip" DefaultValue="Open Editor" />
<bt:String id="ACME.GetStarted.Description" DefaultValue="Test add-in has been loaded succesfully. You can access the editor in HOME tab, click Open Editor" />
</bt:LongStrings>
</Resources>
</VersionOverrides>
</OfficeApp>

Answer 1

I confirmed the image referenced in your IconUrl is 32x32. Based on what you've posted, I don't see a problem with your image. I suggest re-submitting and mentioning that you couldn't replicate the icon issue from the previous failure.
There are a couple of issue with your manifest that you should address first:
The requirements element should come immediately after your hosts element. While this shouldn't effect the add-in, it is tripping up the automated validation script. Simply moving it after hosts will eliminate this being incorrectly flagged during manifest validation.
You've got a couple of references to http://tesaddin.local/index.html. Add-ins are required to operate over a secure transport (https). The only URIs in your manifest that should use http are the XML schema references. Given the .local, I assume this is just a standing URL for posting on SO so this may not be an issue in your actual manifest.