Publishing videos to LinkedIn platform only - annoying bug?

When I try posting a video on LinkedIn platform only (which means I have the Twitter platform de-activated for that post from the beginning), it tells me "Images can't be more than 5 MB". To actually be able of doing it, I am obliged to make a Twitter+LinkedIn post with my video first, and then turn off the Twitter platform option to keep only the LinkedIn post. This way, my LinkedIn post keeps the video that I was not able of uploading if I started from a LinkedIn-post only from the beginning. This seems to me like a very annoying bug.