Macro and append queries

[Amateur]

I have the following problem:
- I have some append queries which are updating tables.
- I have a Macro which is executing those queries.

Now,
* If I run every single append query one-by-one manually, all the tables are
getting updated correct.
* If I run the Macro all tables are getting updated but, one field in one
query gets data which is not in the append query (actually, I have no idea
where it gets those data from).
* If I run the Macro twice, all the transferred fields are correct.

How can it be that the Macro is not working for that field, if I run the
Macro once?
I always thought that, if I run a single append query manually and all data
is correct, than it should work as well if I run this append query through a
Macro.

Any ideas what is wrong?
Thanks
Klaus