Sharepont Designer saves AND/OR CAML Query groups incorrectly

Question

My objective is to display active tasks on a certain date: Started on or before and Due on or after; Started on or before and not Completed.  The date is provided via a webpart connection parameter.
I used CAML Designer 2013 and SP CAML Query 2013 to verify and then modified the Query string for the Tasks WebPart in Sharepoint Designer as follows:
<Query><Where>
<Or>
<And>
<Leq><FieldRef Name="StartDate"/><Value Type="DateTime">{ParmMeetingDate}</Value></Leq>
<Geq><FieldRef Name="DueDate"/><Value Type="DateTime">{ParmMeetingDate}</Value></Geq>
</And>
<And>
<Neq><FieldRef Name="Status"/><Value Type="Text">Completed</Value></Neq>
<Leq><FieldRef Name="StartDate"/><Value Type="DateTime">{ParmMeetingDate}</Value></Leq>
</And>
</Or>
</Where></Query>
However, when I save the page in SharePoint Designer, and edit the web page from the browser, the Filter criteria are:
Start date Less than or equal to {ParmMeetingDate}
AND DueDate Greater than or equal to
AND Task Status is not equal to Completed
OR Start Date is less than or equal to {ParmMeetingDate}
If I correct the settings in the browser and save, the Query String in SPD is changed to:
<Query><Where>
<Or><Or>
<And>
<Leq><FieldRef Name="StartDate"/><Value Type="DateTime">{ParmMeetingDate}</Value></Leq>
<Geq><FieldRef Name="DueDate"/><Value Type="DateTime">{ParmMeetingDate}</Value></Geq>
</And>
<Leq><FieldRef Name="StartDate"/><Value Type="DateTime">{ParmMeetingDate}</Value></Leq>
</Or>
<Neq><FieldRef Name="Status"/><Value Type="Text">Completed</Value></Neq>
</Or></Where></Query>
How can I get SPD/SP to save the CAML query correctly?

Answer 1

Update:  Another effect of the problem outlined above was that no results were displayed for any parameterised filter values - regardless of the query.
I came across a reference to the Server Render webpart attribute.  When this attribute is selected on the webpart a number of things happen:
The Timeline at the top of the Tasks list view webpart is switched off
The completed icon changes to a Yes/No value
The filters work!!!
Saving the filters works!!!
The List View Tools tab appears in SharePoint Designer!!!
I have no idea what the Server Render attribute is and/or why it is set off by default.  I don't why it affects the appearance of the List View Tools tab in the ribbon - I can't think of any reason why it should.  And I don't know why it affects
the filter query or why it should...
At a high level I presume the Server Render attribute tells sharepoint to process on the server rather than on the client.  It may make sense to pas the processing from the server to the client.  It makes no sense that this would restrict functionality
(disable List View Tolls in SPD) or produce different results (no results in Filtered webpart).
Do you know if this issue has been identified as a bug; has it been resolved?