Are the Prius prone to rust at the lower front edge of the front doors?

Both front doors on my 2017 are showing rust at their lower front edges. On the driver door, it even started to show from the outside. Is this common for the Prius to rust there? I took out the rubber grommet nearest to the edge, blasted some air and then applied Fluid Film in and out, hoping to slow down its progression.

I wanted to clean it better from within the door through the speaker opening but that speaker is riveted in place! What? Why do that! Anyway, that's the best way I found. Any tips to slowdown its progression even further?

Thanks

 

no to what? Prone to rust there or ways to slow down progression?

 

Ok, thanks.

 

Last year, I applied OSPHO on the inside of the door (riveted out the speaker to have access), removed the original caulking, cleaned it up, repainted it (only had a paint pen then) and applied a new caulking bead. The passenger side which only started rusting from the inside hasn't continued and looks rust free but the driver door is becoming worse. Rust is starting to burst on the outside I've bought Bondo, Blue Magnetism spray paint, cleat coat spray and clear coat blending spray. My idea is to remove all the rust, use OSPHO, Bondo the repair, sand, repaint the area, clear coat it and use the clear coat blending to 'blend' the new clear coat with the old. Waiting for the temperature to be milder. Because of the location, I might have to remove the door (or the fender, depending what's the easiest) so I don't damage the fender while working on it. Another reason why I'm putting it off lol.