Sub-grid issue

Hi

I have a sub-grid on my Contact form, showing some related records.

I have 2 users with identical roles (business unit, team, security roles, field sec roles). When the users access the same contact, 1 user can see records in the sub-grid and the other cannot. The user who cannot, is able to see the records when search for them via an advanced find. I'm totally confused.

Any ideas??

Thanks,

Rich