This has been discussed in other gen5 threads. As I recall, this is not rust but discoloration caused by residue/contamination left on the metal prior to painting. Simply a cosmetic issue; no need to be alarmed.
From @daisy555 picture in the link, looks like the same sort of pre-paint debris present: The still painted but bubbly zones, next to rust? [Apologies for misplaced image: iPhone IOS 26.1 is driving me spare] <fixed on pc
Thanks!!!!!!!!!!!! I got it. Thank you for your reply!!!!!! I think if the paint is intact, it would not be rust in the future. Because below the bubbly zones just some debris.
