It seems like what is happening is that deposits and withdrawals are getting stuck in SR's system. What I mean is, withdrawals are registering within SR so that the bitcoins are taken out of accounts as usual but then they get stuck somewhere before registering on the network, and never appear on blockchain. Similarly, with deposits, they make it to SR but then get stuck somewhere before being credited to the user's account. This reaffirms to me that maybe all that needs to happen is for SR Support to push the "stuck" transactions manually in both directions.