I haven't seen the CDC whistleblower data, but I've come across a study showing a similar finding (link below) that childhood chickenpox vaccines do increase the risk of shingles in the short-term but reduce it in the long-term, still arguing in favor of long-term benefits.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6015493/

I did not delve into this topic in-depth but assuming the study is robust and true, it may not necessarily apply to adult shingles vaccination.

Regarding vaccines and encephalitis, I see that there're case reports on that, mainly concerning mRNA vaccines. While that is concerning, we have to understand that vaccines are not risk-free because vaccines mimic the actual infection in a safe manner (at least as safe as possible). As a rule of thumb, infections are more dangerous than the vaccines.

And if infections could reach the brain and increase the risk of dementia, I think it's biologically plausible for vaccines to reduce dementia risk.