thanks bart - I was able to determine that it is not working for format ids 43, 168 and 169 - and yes, I do recognize, that if 't1' does not resolve to a value in the data, regex extraction would fail - my question was mostly - why doesnt this seemingly correct regex -

<numFmts count="7">
<numFmt numFmtId="43" formatCode="_(* #,##0.00_);_(* \(#,##0.00\);_(* 
+&quot;-&quot;??_);_(@_)"/>
<numFmt numFmtId="164" formatCode="[$-409]h:mm\ AM/PM;@"/>
<numFmt numFmtId="165" formatCode="m/d;@"/>
<numFmt numFmtId="166" formatCode="ddd\ mm/dd/yy"/>
<numFmt numFmtId="167" formatCode="0.0%"/>
<numFmt numFmtId="168" formatCode="&quot;$&quot;#,##0.00"/>
<numFmt numFmtId="169" formatCode="m/d/yy;@"/></numFmts>
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$member_styles -> contents =~ /numFmtId="$t1" formatCode="([^"]*)/;
my $formatCode = $1 || '';
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