It's not only the MRNA its your own immune system being affected by the invader
Yes, the immune system reacts to the spike protein from the Moderna mRNA being presented in the MHC-1 of the cell. And the Dendrite cell floating by, that recognizes it as foreign has no ability to know if the spike protein fragment came from a Moderna mRNA vaccine, or from a Corona virus. It merely reacts to it to initiate the acquired immune response. That's the whole idea of a vaccine! It stimulates Ab/T cell production, specific against the antigen detected.
as well as how your immune system reacts to new infections. Nobody knows.
Nonsense. Provide a link to whatever you are talking about.