Redstone seems to stop working after a while. The Redstone repeaters, comparators ECT seem to stop accepting the Redstone charge. I've had this issue when realms were first released on bedrock edition but after time it went away. The only current fix I can do is to either replace all the Redstone when it happens (very annoying) or download my realm to my console and then re-uploaded it back to the realm. The second option I feel has to re build everything when uploading so this is by far the quickest fix.