MCPE-20296 (along with MCPE-22515) appears to be reporting a visual glitch of redstone that resolves itself after the next redstone status update. This bug report (MCPE-2370) is not just visual. The torches do not eventually update after status changes. Flipping a connected level over and over will not correct the issue.
Sorry, I didn't come across MCPE-22181 in my original search for some reason. I found MC-579 which was resolved with /entitydata... {invulnerable:1} which isn't allowed in MCPE. Thanks for the update.
MCPE-20296 (along with MCPE-22515) appears to be reporting a visual glitch of redstone that resolves itself after the next redstone status update. This bug report (MCPE-2370) is not just visual. The torches do not eventually update after status changes. Flipping a connected level over and over will not correct the issue.