apparently running into bug 4476 with Saxon 9.9.1.7

Hello,

After updating to Saxon 9.9.1.7 (HE), a stylesheet that used to work 
fine now produces an error, namely

Type error evaluating (fn:collection(...)) in xsl:for-each/@select on 
line 107 column 153 of new_zettel.xsl: XPTY0019: The required item type 
of the first operand of '/' is node(); the supplied value 
xs:base64Binary [...] is an atomic value

What produces the error, apparently, is the following code:

<xsl:for-each 
select="collection('/home/wolfhart/Desktop/.?select=export*.fods')/office:document/office:body/office:spreadsheet/table:table/table:table-row">

It seems to me that this error is related to the following bug:

https://saxonica.plan.io/issues/4476

But, according to this page, the bug was fixed in Saxon 9.9.1.7. So I 
don't understand why I am getting the error.

What is the solution to this?

Thanks in advance for your help.

Wolfhart