That happens if the style in the receiving document has indentation set up
as part of the style's definition.

You can prevent that from happening if both documents are based on the
identical document template and if direct formatting isn't being used
(direct formatting is formatting that is different from the style's
formatting).

You best bet probably is to redefine the style in the underlying template so
that the style used for your table(s) does not contain the indendation, and
make sure that style change is saved to the template.