Whitespace inserted when formatting cell parts via XSLT - excel

Question

I need to format portions of an Excel cell based on a variable. Each time I try I get rouge whitespace that I cannot understand. As a test I made a very simple xsl that was devoid of any real code to try to understand what Excel was doing. I'm still at a loss as to how to avoid the end result. I've removed whitespace within the XSL, since I know this can be an issue with WordML, I've tried to enclose the text via CDATA, I've tried using xsl:text and disabling escaping, and I've tried using normalize-space. In the end the result is always the same (except normalize-space which is logically one space shorter; but the base result applies).
My testing XSL, which can be run with any XML given it isn't actually doing a transform.
<?xml version="1.0"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns="urn:schemas-microsoft-com:office:spreadsheet" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:x="urn:schemas-microsoft-com:office:excel" xmlns:ss="urn:schemas-microsoft-com:office:spreadsheet" xmlns:html="http://www.w3.org/TR/REC-html40">
<xsl:output method="xml" encoding="UTF-8" indent="yes"/>
<xsl:template match="/">
<Workbook>
<DocumentProperties xmlns="urn:schemas-microsoft-com:office:office">
<Author>Developer</Author>
<Created>2018-02-01T15:43:59Z</Created>
<Version>16.00</Version>
</DocumentProperties>
<OfficeDocumentSettings xmlns="urn:schemas-microsoft-com:office:office">
<AllowPNG/>
</OfficeDocumentSettings>
<ExcelWorkbook xmlns="urn:schemas-microsoft-com:office:excel">
<WindowHeight>12345</WindowHeight>
<WindowWidth>25200</WindowWidth>
<WindowTopX>0</WindowTopX>
<WindowTopY>0</WindowTopY>
<ProtectStructure>False</ProtectStructure>
<ProtectWindows>False</ProtectWindows>
</ExcelWorkbook>
<Styles>
<Style ss:ID="Default" ss:Name="Normal">
<Alignment ss:Vertical="Bottom"/>
<Borders/>
<Font ss:FontName="Calibri" x:Family="Swiss" ss:Size="11" ss:Color="#000000"/>
<Interior/>
<NumberFormat/>
<Protection/>
</Style>
</Styles>
<Worksheet ss:Name="Sheet1">
<Table>
<Row>
<Cell>
<Data ss:Type="String">1 TEST</Data>
</Cell>
</Row>
<Row>
<Cell>
<ss:Data ss:Type="String" xmlns="http://www.w3.org/TR/REC-html40">
<Font html:Color="#000000"><![CDATA[2 ]]></Font>
<B>
<Font html:Color="#000000"><![CDATA[TEST]]></Font>
</B>
</ss:Data>
</Cell>
</Row>
<Row ss:Height="18.75"><Cell><ss:Data ss:Type="String" xmlns="http://www.w3.org/TR/REC-html40"><Font html:Color="#000000">3 </Font><Font html:Size="14" html:Color="#000000">TEST</Font></ss:Data></Cell></Row>
<Row ss:Height="18.75">
<Cell>
<ss:Data ss:Type="String" xmlns="http://www.w3.org/TR/REC-html40">
<Font html:Color="#000000"><xsl:text disable-output-escaping="yes">4 </xsl:text></Font>
<B>
<Font html:Size="14" html:Color="#000000"><xsl:text disable-output-escaping="yes">TEST</xsl:text></Font>
</B>
</ss:Data>
</Cell>
</Row>
<Row ss:Height="18.75">
<Cell>
<ss:Data ss:Type="String" xmlns="http://www.w3.org/TR/REC-html40">
<Font html:Color="#000000"><xsl:value-of select="normalize-space('5 ')"/></Font>
<Font html:Size="14" html:Color="#000000"><xsl:value-of select="normalize-space('TEST')"/></Font>
</ss:Data>
</Cell>
</Row>
<Row ss:Height="18.75">
<Cell>
<ss:Data ss:Type="String" xmlns="http://www.w3.org/TR/REC-html40">
<Font html:Color="#000000">6 </Font>
<B>
<Font html:Size="14" html:Color="#000000">TEST</Font>
</B>
</ss:Data>
</Cell>
</Row>
</Table>
<WorksheetOptions xmlns="urn:schemas-microsoft-com:office:excel">
<PageSetup>
<Header x:Margin="0.3"/>
<Footer x:Margin="0.3"/>
<PageMargins x:Bottom="0.75" x:Left="0.7" x:Right="0.7" x:Top="0.75"/>
</PageSetup>
<Print>
<ValidPrinterInfo/>
<HorizontalResolution>600</HorizontalResolution>
<VerticalResolution>600</VerticalResolution>
</Print>
<Selected/>
<Panes>
<Pane>
<Number>3</Number>
<ActiveCol>1</ActiveCol>
</Pane>
</Panes>
<ProtectObjects>False</ProtectObjects>
<ProtectScenarios>False</ProtectScenarios>
</WorksheetOptions>
</Worksheet>
</Workbook>
</xsl:template>
This results in
I would expect no whitespacing before any of the elements in rows 2 through 6. what really seems strange is that when looked at via Visual Studio Code there is no white space in the file. This spacing appears to be coming via something within the Font and B, but the structure is identical to what you would get when viewing a file created directly in Excel without all the whitespace.