Fundamentally speaking, software can be completely analyzed and its behavior predicted. It can, if it handles "events", timing dependencies that make its behavior difficult to predict -- but these dependencies can be seen without running the software, and a good programmer can ensure graceful failure modes.
The behavior of DNA in a living system cannot be predicted. Changes to DNA do not have predictable outcomes, except in trivial cases where working units are transferred form one organism to another. You cannot predict the long term viability of living organisms, and you certainly cannot predict the viability of "engineered" organisms.
The inability to predict is similar to problems encountered in non-living systems. For example, it is impossible to say whether the solar system is stable (even assuming the sun would last forever).
Living systems go off track much faster than planetary systems. The effects of environmental change, coupled with the effects of competition, predation, and luck, make it unlikely htat a stable designed system could be created by any agency that was not omnipotent.