The Poloniex trading UI doesn't properly sync after closing a position.
- Open any Polo page (I am trading ETHBTC)
- Open a margin position
- Note that the balance has changed (good)
- After a few minutes, close the position using the "Close Position" button
- Wait for "Sync" to finish spinning
After the spinner finishes syncing, the balance is the same as it was in step 3. It should be updated because the position was closed. Sometimes manually clicking Sync again will finally update the balance.