When i have installed Watut on the client on Neoforge 1.21.1 the text and inventory flashes

Setting this config on watut-server.toml > dynamicGuiDontSendConstantGUIUpdates = false to true solved the issue for me. This serves as a temporary fix while the mod author fixes the actual bug with the UI blinking/flashing/flickering whatever you call it.

Mod author's response here.