When Marcus had developed his machine it had been purposeful. He wanted to gain immortality through literally sucking the youth out of a young victim and reprogramming his own aged body with youthful vigour while remaining himself. He had succeeded, except that he had been too impatient for results before fully testing the machine.
The result was as planned, except for his tell-tale wrinkled skin, which failed to rejuvenate. The result caused his involuntary suicide.
Rufus adopted the machine (Mac), but, not realising its shortcoming, hadn't tried to fix it. Mac was imperfect.
Cat was about to find out.