The withdrawal problem was completely unrelated to the delist announcement. What happened is that everyone started unlocking at same time and the backend had to process a lot of transactions, however the backend missed a number of these transactions due to block reogranization on the Ethereum network (https://medium.com/blockvigil/how-we-deal-with-chain-reorganization-at-ethvigil-5a8c06859c7).

The team has started to work on a fix almost instantly after the issue was found and on the next day  a fix was uploaded which allowed the backend to work correctly with the ethereum block reorganization. Just one of the issues you don't know its there until it happens unfortunately.