The following code causes author to appear with full given name even though initialize-with should have made it initials only:
<macro name="noauthor_title">
<names variable="editor">
<name/>
<substitute>
<text variable="title"/>
</substitute>
</names>
</macro>
<macro name="author">
<names variable="author">
<name name-as-sort-order="all" and="symbol" sort-separator=", " initialize-with=". " delimiter=", " delimiter-precedes-last="never"/>
<label form="short" prefix=" (" suffix=")" strip-periods="true"/>
<substitute>
<text macro="noauthor_title"/>
</substitute>
</names>
</macro>

This may be a problem of disambiguation only, since the actual substition logic works OK.

Although the code above contains a nested macro, the same issue happens if you simply use any non-shorthand version of the names element inside the substitute element.