DB Chooser failing in iOS9 - app not allowed to query for scheme

Here's what I have in the .plist file. As you can see, I even tried adding the db-<my_app_key> to LSApplicationQueriesSchemes. Doesn't work with or without that.

<key>CFBundleURLTypes</key>

<array>

  <dict>

    <key>CFBundleTypeRole</key>

    <string>Editor</string>

    <key>CFBundleURLSchemes</key>

    <array>

      <string>db-my_app_key</string>

    </array>

  </dict>

</array>

<key>LSApplicationQueriesSchemes</key>

<array>

  <string>dbapi-1</string>

  <string>dbapi-2</string>

  <string>dbapi-3</string>

  <string>db-my_app_key</string>

</array>

I tried adding some NSLog messages to the code. As you can see, all the work is being done within the closure. But none of the NSLog messages in that section of text are showing up, so it's like the closure code isn't being executed.

One other thing: sometimes I'm also getting network errors (see below). I don't get these every time, and even when I don't the import process is still failing. Having googled this somewhat, I'm under the impression that this error is to do with fallback to cellular if wifi is weak. (Don't know why it's doing this because the wifi signal is strong and everything else - eg, mail, browser - are working fine). Also, this problem with the import isn't just with me - I have a user reporting the same issue. But for the sake of completeness, here's the other error I'm seeing:

Sep 20 08:49:45 Steves-iPhone5 networkd[1251] <Error>: -[NETAWDManager reportStats:metricID:] AWDServerConnection newMetricContainerWithIdentifier failed for metric 2686983, server 0x16e5a9c0, not reporting:
<AWDLibnetcoreTCPConnectionReport: 0x16e8edd0> {
cellularFallbackReport = {
dataUsageSnapshotsAtNetworkEvents = (
{
bytesIn = 5100;
bytesOut = 1000;
},
{
bytesIn = 5500;
bytesOut = 1600;
}
);
"fallbackTimer_msecs" = 0;
fellback = 0;
networkEvents = (
"NETWORK_EVENT_DATA_STALL_AT_APP_LAYER",
"NETWORK_EVENT_DATA_STALL_AT_APP_LAYER"
);
"timeToNetworkEvents_msecs" = (
4240,
40473
);
};
clientIdentifier = "com.getdropbox.Dropbox";
connectionStatisticsReport = {
DNSAnswersCached = 0;
"DNSResolvedTime_msecs" = 58;
RTTvariance = 0;
"appDataStallTimer_msecs" = 3;
appReportingDataStallCount = 2;
"bestRTT_msecs" = 0;
betterRouteEventCount = 0;
bytesDuplicate = 0;
bytesIn = 0;
bytesOut = 0;
bytesOutOfOrder = 0;
bytesRetransmitted = 0;
cellularFallback = 0;
cellularRRCConnected = 0;
connected = 1;
connectedInterfaceType = "INTERFACE_TYPE_WIFI";
"connectionEstablishmentTime_msecs" = 253;
connectionReuseCount = 0;
"currentRTT_msecs" = 0;
"flowDuration_msecs" = 37379869;
interfaceType = "INTERFACE_TYPE_WIFI";
kernelReportedStalls = 0;
kernelReportingConnectionStalled = 0;
kernelReportingReadStalled = 0;
kernelReportingWriteStalled = 0;
packetsDuplicate = 0;
packetsIn = 0;
packetsOut = 0;
packetsOutOfOrder = 0;
packetsRetransmitted = 0;
"smoothedRTT_msecs" = 0;
synRetransmissionCount = 0;
tcpFastOpen = 0;
"timeToConnectionEstablishment_msecs" = 316;
"timeToConnectionStart_msecs" = 63;
"timeToDNSResolved_msecs" = 60;
"timeToDNSStart_msecs" = 2;
trafficClass = 0;
};
delegated = 0;
reportReason = "REPORT_REASON_DATA_STALL_AT_APP_LAYER";
}