Few specific thumbnails were deleted repeatly

Some specific posts have thumbnails and always are deleted automatically after regenerating thumbnail. It’s not happen right after regenerating, may be few minutes, maybe around 1 day and I’m not sure.

Maybe it don’t relevant to Litespeed Image Optimize plugin although .webp images weren’t deleted

This is the most weird thing I met with WordPress. I don’t know which cause it, plugins or hosting or extra things? I have to regenerate these thumbnails daily.

Please give me a help to trace this issue.

Thank you