Catastrophic Tissue Rejection

Oh no. Oh no!

The cloning complexes and technowombs that keeps mankind alive are ancient beyond reckoning. Despite living with them for millenia, humanity have grasped a fraction of their mysteries, and still struggle with mistakes, malfunctions, and evil, wily machine-spirits. Corruption comes in many shapes, but the worst is the Catastrophic Tissue Rejection condition, sometimes called Clonerot, where the engineered flesh of a clone rejects their being. It is a slow, agonizing death-sentence, as even clones that emerge from the pods looking healthy are rotting from within as meat seperates from bone, tendons rebel against tissue, and in some cases parts of a clones body attack the other.
Clones who suffer from CTR are cursed with a body that hates them and will in time do its best to murder them. Those who survive are fortunate enough to have enough of their own corpus on their side to have their doom be inevitable rather than immediate - those with severe cases barely survive their first few steps out of the cloning-pods before their body finds some inventive way to terminate them.
There's no permanent treatment, and no known cause. Some Pods are rumored to be cursed or haunted, and clones that emerge from it are more likely to emerge with CTR. Clones so cursed are treated as something akin to walking dead, and banished from much of normal life. On the other hand, to Somaturges they are fascinating cases and excellent material to create living, biological weapons.

Example Horros

Hair that grows into the scalp in an attempt to smother it, causing abscesses and scabs. It must be shaved and plucked regularly to keep it from the skull.
Nails that grow in reverse to try and consume the fingers. Most sufferers remove the tip of their fingers and toes as a permanent solution.
Tendons that wrap around bone to strangle them. There's no treatment beyond the most invasive Somaturge treatment
Stomachs that overproduce acid until it melts out of the patient.
Muscles that exert far beyond safe limits at the most inopportune times.