That is not good, it should default not to flowblind, as that effectively disables the flow-queueing part of cake, I wonder why it does that. I also note that 18.06.1 is not the most recent version, so I would kindly propose to re-test with at least 18.06.2 (or if you wait a few days 18.06.3 or 4 or even 19.07.1)
There seems to be something wrong, but first let's figure out wether we are chasing an already fixed bug 
P.S.: It generally is better to open a new topic, you can always link in the thread you came from/ wanted to respond in your first post, but having individual threads that can achieve a solution seems overall nicer than open-ended threads collecting similar issues.