Yes, it does look like they are going to delist FSN and 25 other assets due to new requirements and regulatory overhead in South Korea.
This is particularly scary because the Upbit address has been actively buying and selling lots of FSN in the last year of which 1 million FSN was recently moved into their "hot wallet" and about 700k already dumped today.
But we need to separate Upbit as an Exchange and Upbit as an investor.
Upbit as an Exchange
Let's start by the exchange, because they've historically acted in a highly unusual way for an exchange. Fusion has throughout its history held a policy to never pay any listing fees, and with that in mind it's quite impressive how many exchanges it has made it onto. But in the case of Upbit it's even more impressive, because there's never really been any official channel of communication with upbit.com, they have seemingly fully on their own initiative, without in depth communication, both listed FSN and properly migrated their FSN-holdings to Fusion mainnet.
They have also on several occasions closed deposit and withdraws, which resulted in odd internal pumps of FSN, far removed from true market price.
They have now twice threatened to delist FSN, and this time it might be happening. It's likely a real thing that they need to get rid of some assets to secure their own future as an exchange and unfortunatly FSN has fallen onto this list of sacrificed assets. It's a situation very familiar to what happened with Bittrex (US) in 2019 (FSN wasn't in the cross-fire than, but lots of assets were). The reason why FSN ended up on the list might be that they don't have enough real trading on it on their exchange.
Upbit as an Investor
Despite lack of communication and constant threat of delisting crypto addresses connected to Upbit.com have been extremely active in trading FSN on Huobi. In fact they are probably the most active market maker FSN has, both buying and selling, but above all they have been buying accumulating very large stacks of FSN most of which have been bought at a price far above the current one.
Will an Upbit delisting change this? Current activity points to a sell-off, but will it continue?
I'd say this is a possibility, but it might also be part of a plan to acquire even more at a cheap price. Because delisting does not necessarily mean selling off holdings. This is evident if you look at BitMax wallets. They delisted FSN a long time ago, but never really sold it off. A former exchange can thus still remain a holder or even an investor.
Upbit is facing a tough time in South Korea. It's likely not easy for them to have regulatory overhead come down on them with new demands. All CEXs are facing similar issues and it may get worse and worse in the coming years. This may also affect what they choose hold and invest in. Perhaps they, like many others, see DeFi as a more prosperous future than CEX markets. Getting a good edge in this new market, while dealing with their problems may not be a bad idea. Perhaps this is why they've gotten heavy holdings of FSN, perhaps not?
I don't really know, but I do know that how they've acted as an exchange and as an investor certainly hasn't meshed in the past, so think carefully before acting, on the Upbit delisting news, as things aren't always as they seem.