Created attachment 87177 [details]
Example file demonstrating the error.

File spreadsheetml2ooo.xsl has already been patched in version 4.1.14 (Issue 81233) but now references columns above 676 are wrong. Below is a patch for spreadsheetml2ooo.xsl replacing templates translate-unit and number-to-character.
Files uof2odf.xsl and uof2odf_spreadsheet.xsl contain a wrong version of translate-unit as well.

	<xsl:template name="translate-unit">
		<!-- convert cell position expression unit, R1C1, R3, C4 -->
		<xsl:param name="column-number"/>
		<xsl:param name="row-number"/>
		<xsl:param name="column-pos-style"/>
		<xsl:param name="row-pos-style"/>

		<xsl:variable name="ColumnLetters">
			<xsl:call-template name="ConvertColumnNumber">
				<xsl:with-param name="ColumnNumber" select="$column-number"/>
			</xsl:call-template>
		</xsl:variable>

		<!-- position styles are 'absolute' or 'relative', -->
		<xsl:choose>
			<xsl:when test="$column-pos-style = 'absolute'">
				<xsl:text>$</xsl:text>
			</xsl:when>
		</xsl:choose>
		<xsl:value-of select="$ColumnLetters"/>

		<xsl:choose>
			<xsl:when test="$row-pos-style ='absolute'">
				<xsl:text>$</xsl:text>
			</xsl:when>
		</xsl:choose>
		<xsl:value-of select="$row-number"/>
	</xsl:template>

	<xsl:template name="ConvertColumnNumber">
		<xsl:param name="ColumnNumber"/>
		<xsl:variable name="letters" select="'ABCDEFGHIJKLMNOPQRSTUVWXYZ'"/>
		<xsl:choose>
			<xsl:when test="$ColumnNumber &lt;= 26">
				<xsl:value-of select="substring($letters, $ColumnNumber, 1)"/>
			</xsl:when>
			<xsl:otherwise>
				<xsl:call-template name="ConvertColumnNumber">
					<xsl:with-param name="ColumnNumber" select="floor(($ColumnNumber - 1) div 26)"/>
				</xsl:call-template>
				<xsl:value-of select="substring($letters, ($ColumnNumber - 1) mod 26 + 1, 1)"/>
			</xsl:otherwise>
		</xsl:choose>
	</xsl:template>