I vaguely remember reading somewhere that this was a bug...but I can't be sure. Any ideas?
Also, it looks like you are have a text wrap on the anchored image?
When the anchored object is Inline it acts like a text character. If you reduced the leading on two lines of text, so the lines overlap the lines below stack on top of the lines above. So the same thing will happen with an anchored object—it will be on top of text above it:
Here I have the anchor at the end of paragraph 1 instead of at the beginning of paragraph two. You can see the text wrap doesn't affect the characters before the anchor in paragraph one:
Text wrap is in the same line where an anchored frame is anchored ignored.
I recommend to use a specific paragraph for the anchor only or anchor it in the paragrph before.