@kayan, great post! I've just had a load of "refill Coolant" warnings this w/e on my travels, so not sure if it's my genuinely-a-bit-low fluid, or the crystals problem starting. My 38 was made in 2019, so one of the earliest, has 25k miles on it.
I'm going to visit the dealer today to chat with the service manager in Southampton UK, they're a large dealership, & see what they say. I just did some digging, very interesting findings!
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EARLY History:
here's a post showing the original Blue coolant as used in my 2019 Ioniq & other BEVs, this is the BSC-1 P/N 00232-19091.
Blue Coolant
... and here's the August 2020 process to swap the HV battery, & refill using BSC-1.
https://static.nhtsa.gov/odi/tsbs/2020/MC-10179247-0001.pdf
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PRESENT Situation:
September 2022, here's a Kia Sorrento guy mentions Crystals forming, and the service guys deny knowing about this, but simply swap the coolant swap the coolant for a new one. To me, this says Kia & Hyundai both have this problem, and clearly know all about it by now. It also suggests to me that every car using the BSC-1 original coolant probably needs it swapping out.
2021 Kia Sorento Hybrid Coolant Refill Warning
But they don't want us all at once, so will doubtless wait until we complain! After all, some of these cars will get written off before any problem shows, so updating these would have been a wasted effort. Can't argue with that...
I've found the TSB 22-HC-002H you revealed, here's a link to it.
22-HC-002H Hyundai Technical Service Bulletin
and refers to "certain Tucson & Santa Fe hybrids" ! Crucially, it mentions "flush debris" and BSC-2 Coolant to be used.
This fits perfectly your post where it states ...TSB 22-HC-002H It's for a different vehicle but follow the same procedure.
You've given me great ammo to have a friendly chat with my local service manager - thanks again!
Edit later same day: BSC-2 Blue Low Conductivity Coolant is Hyundai P/N 00232-19111 acc to the TSB 22-HC-002H