DFU with nrfutil v6.0.0a0 slower than nrfutil v5.2

Hello,

I did a side by side comparison of the latest nrfutil v6.0.0a0 vs v5.2.  It looks like v6.0.0a0 is much slower.

Looking at the log from the target device, it looks like the new version is only sending 20 bytes at a time instead of 244.  

nrfutil v5.2 reports:

2019-10-09 10:02:17,457 BLE: Connected to [208, 137, 193, 106, 28, 248]
2019-10-09 10:02:18,493 Successfully Connected
2019-10-09 10:02:18,496 BLE: Service Discovery
2019-10-09 10:02:19,641 BLE: Enabling longer ATT MTUs
2019-10-09 10:02:19,677 ATT MTU exchanged: conn_handle=0 att_mtu=247
2019-10-09 10:02:19,894 Sending init packet...
2019-10-09 10:02:20,033 Sending firmware file...
2019-10-09 10:02:56,092 Image sent in 36.1979999542s
2019-10-09 10:02:56,092 BLE: Disconnecting from target
2019-10-09 10:02:56,128 BLE: Disconnected with reason: BLEHci.local_host_terminated_connection
Device programmed.

nrfutil v6.0.0a0a reports:

2019-10-09 10:04:56,754 BLE: Connected to [208, 137, 193, 106, 28, 248]
2019-10-09 10:04:57,755 Successfully Connected
2019-10-09 10:04:57,755 BLE: Service Discovery
2019-10-09 10:04:58,706 BLE: Enabling longer ATT MTUs
2019-10-09 10:04:58,887 Sending init packet...
2019-10-09 10:04:59,340 Sending firmware file...
2019-10-09 10:09:49,185 Image sent in 290.2987735271454s
2019-10-09 10:09:49,185 BLE: Disconnecting from target
2019-10-09 10:09:49,242 BLE: Disconnected with reason: BLEHci.local_host_terminated_connection
2019-10-09 10:09:49,247 serial port COM7 closed.
Device programmed.

There seems to be a missing confirmation that the MTU has changed to 247.

In the device log:

It looks like there is an update request that doesn't happen with 6.0.0a0.

Is there something I'm missing with v6.0.0a0?

Thanks,

Jim