[s]Eh? Well the only reason that would happen is if the template code is still trying to display something.
Try changing your
memberinfo_block_xblinfo template to this (in addition to the plugin change):
Code:
<if condition="$block_data[xblinfo]">
<div class="alt1 block_row">
<ul class="list_no_decoration">
$block_data[xblinfo]
</ul>
</div>
</if>
See if that clears things up.

Template caching could be affecting the output.[/s]
Shouldn't be necessary anymore, figured out the original modification to this mod used the wrong variable name.