Whether a disease resistance of 100% is gained from Beast Blood or from a Necklace of Disease Immunity, diseases can still be contracted. This is due to one of two things:

• Disease resistance is subject to a cap similar to other resistances (~80%), or
  
• Disease resistance is broken and does nothing

If it is the former, than items shouldn't imply immunity when no such thing is possible. Obviously, if it is the latter, it needs to be fixed.
It has also been reported that poison resistance of 100% and poison immunity does not prevent poison damage. Both of these issues have been verified on 1.3.10.0 with no mods present.

Thanks for the info but I think the mods and/or maybe Gstaff want bugs to be reported here

http://www.gamesas.com/topic/1317665-unofficial-buglist/