La-la land after stopping a sequence

[jfburke3]

Phone: Samsung Galaxy S7 Edge Android ver: 7.0 (AT&T baseband version QJ2) -- BUT, has happened on previous releases, including Android 6.0.1 on this phone) OSC version: 2.1.5 -- BUT, has happened with numerous earlier versions, too.

Problem description: After stopping a sequence, I usually see the a colored track running around the start/stop button in a circle. Most of the time, it stops after a few seconds, and I can start a new sequence. However, sometimes, the running track never stops. I've let it sit for 10 minutes and more, and it never ends. I am unable to start a new sequence until it finishes, yet when this problem crops up, it never does. Exiting the app by pressing the phone Back button and answering Leave doesn't help, nor does killing the app itself. The only thing that seems to "fix" it is to completely power off my phone, then power back on.