Hello Pablo,
I am not a sediment transport specialist, but:
- you should first use the latest release and see if you still have the same issue,
- but I would recommend you to use GAIA which is the new sediment transport module which can be coupled with both TELEMAC-2D and TELEMAC-3D, and is now the only sediment module which is developped and maintained in the TELEMAC-MASCARET system. You should get more features to model sediment in 3D.
Hope this helps,
Chi-Tuan