Box and Salesforce - Periodically Disconnects

Hi, I set up Box for Salesforce and it's working well, but we're finding that periodically users need to reconnect to Box even though all users access both salesforce and box via SSO.  This tends to come in waves which lead me to think that it was related to users periodically resetting passwords, but with SSO this isn't the case. 

It's not immediately apparent in Salesforce when this happens as users don't immediately notice that the Box component is no longer displaying the files from the box drive on the record, but it causes this very unhelpful "Error!" banner which also does not let the user save edits to the Salesforce record.  Once the user goes into the Box app and reauthenticates Box, this issue is resolved.  But I haven't been able to identify the root cause of Box disconnecting. 

Any ideas?