The damage may not be permanent. Some cleaning solution residue can be very difficult to remove. HG provides very little detail on the what is in the cleaner other the standard market speak - HumminGuru The Small Bottle | Ultrasonic Vinyl Record Cleaning Agent. Also, distilled water DIW that is a year old can have very high total dissolved solids (TDS) and can go acidic. DIW absorbs CO2 which then forms carbonic acid leading to lower pH and higher TDS. It all depends on how much air it and for how long it was exposed.
I would not yet give up hope. Try recleaning one more time with fresh DIW and if you are in the USA, my go to simple nonionic surfactant is Tergitol 15-S-9 you can purchase here Tergitol 15-S-3 and 15-S-9 Surfactant | TALAS (talasonline.com). One-pint will last you forever, and disregard DOWs 2-yr shelf life, I have Tergitol 15-S-9 that is 5-yrs old and is fine. Just store in a cool dark place. For use, download the latest version (3.1) of this book Precision Aqueous Cleaning of Vinyl Records-3rd Edition - The Vinyl Press and look at Table XXIII, Nalgene™ Dropper Bottle Use for Degritter™ & Humminguru™ for directions on use.
For those in the UK & EU, Polysorbate 20 is an alternative you can generally purchase which the book addresses.
Good Luck,