It sounds like what you are doing is producing the correct result, but you
seem to be expecting something different
Inserting a Table *Placeholder* on a Master does exactly that - it provides
a device for adding a table to a slide & defines the area where that table
will be inserted. A slide based on that master will have a placeholder [of
whatever size you designed it] containing an icon & the bulleted instruction
"Click icon to add table". Clicking the icon produces a small dialog for
specifying the number of columns & rows, clicking OK then will add the table
to the slide, replacing the placeholder. IOW, it works just like the Content
Placeholders provided on the default layouts except that it only has the one
icon for producing a table rather than the cluster of six icons.
It sounds as though you are expecting a table to actually be created on the
Master, which is not what a Layout Placeholder is/does. You can create a
table on a layout master if you use the regular Insert> Table command to do
so. It can be sized & formatted just like any other table & you can add
whatever content you wish - BUT the table that appears on slides generated
from that master will *not* be editable on the slide. That's the intent of
Master Slide objects - just like logos or other content 'on the master' it
appears as designed & wherever placed on each slide generated from that
layout & cannot be edited or deleted.
If you're trying to control the number of rows/columns and/or the default
formatting of newly created tables in a presentation, this isn't the way to
go about it
AFAIK, the number of columns/rows cannot be predetermined, &
the default format is determined by the Theme used by the master.
HTH |:>)
Bob Jones
[MVP] Office:Mac