Yes it is. Pitch them.

Dave

SanMarzano and Roma are notorious in that characteristic.
Why that happens ? There are theories. But genetics is also a big factor. That is why I, personally, have said "NO" to Roma and SanMarzano, based on my past experience. I have pitched sooo many of them in the past with anger. YMMV

dang it. anything to be done? or just pitch those and cross fingers for the next fruit?

this plant has had problems from the beginning - i think maybe the moisture wasn't consistent enough - the tomato next to it is fine however.

Pitch those, cross fingers, and if in containers stabilize the moisture. When in the garden in ground the problem usually resolves itself as the plant matures and the weather settles. In containers it is a whole different ballgame that the grower has to stabilize.

Dave

Read the FAQ re BER:

http://faq.gardenweb.com/faq/lists/tomato/2012053239011914.html

The key:
Be a fanatic about evenly moist growing mix.

Here is a link that might be useful: the FAQ re BER

thanks jean and dave! it is in a 18" high raised bed, filled with native soil (sandy loam in the LA river floodplain) with lots of composted organic matter worked in before planting, open bottom to more native soil. hopefully stabilizing the water will help. san marzanos must be more sensitive to it - my sweet 100, sungold and first lady II so far are okay though in same conditions. (so far....knocking on wood...)

All paste types are more prone to it due to their shape.

Dave