Hi Pat
I’m a book publisher and come across this all the time. It’s not a bug as such, just an undesirable behaviour.
David is right in saying that the image can’t fit at the bottom of the page. What’s happening is that the ‘music left’ object style has “Keep within top/bottom column boundaries” checked in the Anchored object options. An object that is anchored such that it sits below the baseline of the paragraph it is anchored in does not affect the vertical space of the paragraph – if the object has no text wrap, it will overlap anything below it. Applying text wrap will push following paragraphs down if necessary, but it doesn’t change the vertical size of the paragraph where the object is anchored. This is the key thing, because it means as you get towards the end of a frame, as long as the paragraph itself fits in the frame then an anchored object extending below beyond the column end does not force it to the next one. Indesign does give the option to keep within boundaries as above and this is generally good for tops of frames but not so much for the bottoms.
There is a workaround using a table, which is straightforward provided you don’t need text to flow around the graphic. Because tables sit in a paragraph, you can use a paragraph style for positioning, keep options and spacing (and span if you’re working with columns), then create a 1×1 table in the paragraph to contain the graphic (thus it is “anchored” and flows with the text). After you create the table, select the cell and go to Table > Convert Cell to Graphic Cell, then place or paste the content into the cell. You can specify an exact row height in combination with frame fitting options if you want consistent sizes. Bart Van de Wiele did an excellent tutorial on this site that I highly recommend even though it is based on graphics within a larger table, search for Indesign How-To: Place Images in a Table Cell (also on YouTube on InDesignSecrets channel).
I don’t generally like using tables for layout, but sometimes they are a useful substitute for an object frame.
Hope that’s of some help.
Nick