Patterns in TChart show not requested (not always!)

We built a beta of our application using BCB4 and TeeChart 402 pro.
The beta was released to 10 beta-tester final users (on IBM ThinkPad).
Many of them reported the charts use patterns instead of filled colors
as expected.
Others have no problems. All of them use the same built and same
which actually are cloned. In the code there is no reference to patterns
at all.

Moving the hard disk from a machine with this problem to a regular one
makes the second machine reproduce it.
We cannot reproduce it on our development machines.
Any idea about where to look for the reason?

TIA,   Mauro