RTT log output is delayed

I'm writing some DVT tests what I'd like to see the output from the test display in real time on a RTT log.  By real time I mean that if a log statement prints something, I'd like to see it appear in the log within a second or so.

What I'm seeing is that the output doesn't appear until after my program has completed.  I'm using deferred logging and am periodically processing the log in the loop that executing the test.

I'm using SDK 15.3.0 with SES 4.20 running on a nRF52840 DK.

I've created a small project that illustrates what I'm seeing with documentation on the actual output verses the expected:


The project is setup for CI and the hex files that I'm testing with can be downloaded at:


I'm sure I'm missing something simple but just can't find it.  I'd appreciate any suggestions as to what I might be doing wrong.