Such situation was described in the 5th Robot webinar which recordings I strongly encourage you to watch from:
http://forums.autodesk.com/t5/robot-structural-analysis/robot-structural-analysis-webinars/td-p/5523...
The suggestion for such situation was:
"Make sure you define reinforcement zones in such a way they cover whole slab for each reinforcement type. In case you see this situation for automatically generated ones try to switch to the regular grid type and run reinforcement generation again"

or use the suggestion from post 23 from: http://forums.autodesk.com/t5/robot-structural-analysis/model-warnings/td-p/5169033
The other situation has been described in:
post 3 from http://forums.autodesk.com/t5/robot-structural-analysis/slab-reinforcement-problem/m-p/3924851
If you find your post answered press the Accept as Solution button please. This will help other users to find solutions much faster. Thank you.

Artur Kosakowski