I am not coming to my opinion because a blogger said it. I am looking at the markings myself: It looks like a triangle to me. If you open the video you can see for yourself.
I also have to question your original screenshot which conveniently hides the marking. Was this takem from the Forbes article? Y/N. If Y: David Axe? Y/N.
And finally, if you watch the video, there are some things about it that suggest Russian forces have a very solid idea of what is happening in the area. As some of us have been saying, sending AFU into this areas is probably a terrible idea.
