There is a bug on Minecraft Bedrock edition that has been happening for years now. When you take damage and your health goes down it doesn't flash 3 times like it should, When you heal your health should flash twice every half heart but it doesn't flash at all. On Java Edition your health flashes 3 times when hit and flash 2 times when healing. It's a visual glitch and must be fixed, The glitch looks unappealing for new players.