Might be down to a node in the specilization tree, but Locust swarm generated by Swarm strike on Druid’s Swarmblade persist visually after it runs out. It also spawns in the visual after every loading screen for me and it does stack the effect every time.
This will get so bad that it slows down the game and eventually crashes it.
https://imgur.com/qjl9Xgx