i was playing 
in the jungle and started with blue buff, when i attacked blue buff with bot lane 
and 
blue buff would hit my rarely and kept walking out of its spot which kept resetting its health bar back to full when it went to far. (did this until blue buff was killed then went back to normal)
Banbutsu Sozo1 votesHappened with me. Maybe it's all knock ups? Did Janna Q it? It just happened to me when a bot lane with Rakan support leashed it.
GearX19991 votesjust watched a replay on my game and that's exactly what happened it was attacking me doing its normal thing until janna's Q hit it then it started walking out of range and resetting its health
Right Boobie1 votesI'm so pissed about this, happened with my wraiths and blue buff as well. Lost the game obviously since my level was so much lover than everyone else's. Goodbye LP.
Polske1 votesYes, it's a known bug of the last patch. https://boards.na.leagueoflegends.com/en/c/bug-report/uWjjRv7k-gameplay-red-brambleback-keeps-resetting