Red triangle above mouse - Minecraft Java UI pack

Well I have Ben using a Minecraft Java UI to make bedrock look like java but until the recent update (Update 1.16.100 at 11/17/2020) There has ben a strange red Triangle above the Hotbar or Mouse. I think this might effect other UI's Texture packs but I just want to know how to remove it. 

Thanks,

Local Spy 51

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