It might be because of the unfinished nature of this draft, but I really don't understand what is happening at all with this. It talks about a man and a burger and then it goes on to say we can't distinguish between the two? Even more confusingly you mention that SCP-XXXX instances decay after a couple of weeks and lose their anomalous properties - does that mean the man also dies?
There doesn't seem to be much of a story present either though im going to place that as a result of the draft's unfinished nature. Currently its just an effect tacked onto a burger and a man - these objects could be replaced with just about any other object and nothing in your SCP would change besides some minor description and containment details, so you need to work on providing us with a good story explaining how the effect occurred.
I can think of several interesting ways to take this; maybe a poignant comment on modern day obesity and a spin of we are what we eat. Won't dwell to much on technical crit since a lot of it will probably get changed but I do recommend rewording:
SCP-XXXX refers to an entity possessing two identities simultaneously. These identities are designated SCP-XXXX-A and SCP-XXXX-B.
To: SCP-XXXX is the collective designation for two entities classified as SCP-XXXX-A and SCP-XXXX-B.
Thats all good luck with your draft.