Sounds reasonable to me. But I'm a mechanical engineer, not a body engineer.
The blueprint RNA messenger is delivered into the cell inside a lipid nanoparticle. When that lipid nanoparticle fuses onto a cell wall membrane, it releases the RNA Messenger into the cell, where the host cell’s ribosomes read the RNA instruction to translate the proteins that are exact copies of the C-virus Spike Protein. These proteins are then presented on the surface of the host cell's membrane where they bind to the MHC-1 and MHC-2 complex molecules. The MHC-1 complex is where these proteins attract T helper cells. Once in contact with these foreign proteins there is an interaction with the T helper cells which trigger them to produce cytokines (interlukens) and memory cells. The interlukens attracts B-cells (from the lymph nodes) that produce plasma cells which act to produce antibodies that will bind on the C-virus's Spike Protein, whenever present, neutralize it and destroy it. It is not known how long these specially programmed antibodies stay in the body.
The memory cells, however, will produce T-cells (from the lymph nodes) that are programmed to produce antibodies that will also attack any future C-virus’s Spike Proteins that enter the body. This function should last a long time.
Proteins on the host MHC-2 comlex molecule attract cytoxic T-cells that release destructive molecules that destroys the host cell, ending the Spike Protein reproduction.
If it was a normal and expected response to a vaccine they claim 90% + efficacy for, then it seems that the enlarged nodes would present themselves in more than 11% - 16%.
Truth is they have zero idea how/why different folks have such widespread/varying responses.