I had this problem for a while. It quit after I uninstalled Lookout and Screen On. Not sure if either of them had anything to do with it.
I then setup a "phone off hook" rule with tasker. If "phone off hook" stay on = never & screen timeout = 5 min
The stay on according to how it is written should not do anything. The timeout also does not seem to keep the screen on, but now it wont lock in the 5 minutes.
So either this tasker code doesn't work and the issue was lookout or screen on, or this tasker code that should not work combines to keep the lock from working. Or the problem went away on its own.
Either way, I am now happy.
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