Camera does not work after upgrading dev build from Q to R on FP3

Note: This is about the dev build, not the stable build. They sometimes have different issues.
I upgraded my FP3 from 1.5-q-dev to 1.6-r-dev via adb sideload.
Besides some other issues the camera does not work: the picture part of the app is black . I tried three apps, all the same. OS camera, Open Camera (same as OS camera but most times newer version) Camera-FV-5-Lite. The first two claim that another app might use the camera, the third one that it cannot load the camera driver.
Clearing cache and deleting user data did not help.
Can someone confirm this issue? Is there a solution?

I sorry to hear that it didn’t work for you others had more luck.

Although it probably won’t help: did you try a reboot?

Thank you for your answer. Of course I rebooted the phone, meanwhile several times. Not to make the post to complicated and to see whether it is a known issue I did not mention that the phone is rooted and I used Tasker to unblock the camera only for allowed apps. That all worked fine with 1.5-q-dev.
I en-/disabled Tasker and the related task several times and rebooted, no difference. The same feature for the microphone still works correct. Theoretically Tasker might cause the problem although it says that the camera is unblocked, but I don’t think so. I rather believe that something happened to the camera driver.
Perhaps someone comes by who had the same issue and could fix it.