2016 Tacoma Door Sill Rust

So a little backstory here - I've had my 2016 TRD Off-Road since, well... early 2016 and still love it. But only about a year and half after buying it I noticed a tiny rust spot on the door sill of the driver's side. It eventually spread (like rust does) and was wider than a half dollar.

I eventually went to a place to have the section professionally cut out, replaced and repainted and it looked back to factory. They even mentioned filling some of the spots behind it because water likes to collect. Less than a year after that, the rust came right back! Any suggestions as to what to do with this? Thanks!

 

Ours is a 2017 and I can't say I saw any...yet. I would scrape off the rust, touch it up with some primer and then paint. At least slow at down...lots of humidity down there in New Hampshire?

 

I could try, but I think it's rusting from underneath, which is why it's happening again. And NH just gets the normal amount of rust that most of New England gets - especially from all the road salting in the winters.

 

There's a TSB for this. You're outside of the window but I'd contact Toyota and see what they say.

https://www.tacomaworld.com/threads/t-sb-0021-19-rust-paint-blistering-on-lower-door-sill.598440/