The only way to ensure the mutation does not affect the bots long term, is to produce many bots by the original copy. The more copies made of your original, the better its chances for genetic survival. I am not sure how destroying itself will produce a real evolutionary result many programmers seek in their design. Change your reproductive requirements using numties or something besides body, say robage; bodies take way longer to rebuild over time, so reproduction is slower, yielding possibly 3-5 offspring a generation. No matter what, if you allow mutations there will be mistakes, but you need to use either harsher environment settings, or something along the lines of population control. I have cancerous problems with every bot I ever test, but the environment usually kills the bot from costs and over production without finding more energy to harvest.
As programmers we must utilize everything at our advantage, and that is DB. Mutations are meant to improve and specify your species to see how worthy the genetic code actually is, there will be many failures, so run with large populations, like 80 for large bots, and say 30 for smaller bots (dna len, not mass or radius). There's no need to cause a bot to become sucidal, this prevents many specific cospicuous relations, such as legumes.
