InDesign shows "hidden" Illustrator art at edge of AI artboard

Question

I draw  big sets of maps in Illustrator to be part of an InDesign book layout. The maps are vector art. On a top layer, we draw the map's frame or neatline. The artboard of the Illustrator art extends past the frame (in case we need to quickly shift or rescale the map within the frame). So we manually mask the area beyond the frame with white boxes (on the next-to-top layer below the frame). These masks are plain old vector art, white fill (0,0,0,0); no stroke; 100% opaque, and not set to overprint.
The book designer placed the finished maps in InDesign using plain picture boxes slightly larger than each map.
For several recent projects the designer reports that when the maps' artboard falls inside the picture box,  InDesign displays "ghost image" right where the edge of the artboard would be.  It's a little strip of the art right along the artboard, that is supposed to be masked by our white boxes. It's the same color and position, about 1 pixel wide.
We don't know what causes this; we don't know if it's real (it shows up in proof PDFs). We sure don't want it to print. Printers don't like to see it on our proofs.
We are not sure of the cause or solution. It happens on my InDesign too.
Searching old forum posts from 2009 or so, there are threads on ghost white or black lines in PDFs, often with raster art. But we haven't found any discussions of exactly this problem with vector art.
Also, when we export as Illustrator art with PDF compatibility, we apparently have no choice in what flavor of PDF the art is compatible (whereas some of the old threads' solutions, saving as PDFs, it was useful to chose PDF X-1a or something newer than 2004). So some of the "solutions" on those old threads don't apply here.
On our end (in Illustrator) there are a couple unpalatable workarounds. We can mask the Illustrator art (Object/Create Mask) with a rectangle exactly fit the map frame, but we lose all the layers that are useful for future edits. [FreeHand remembered layers of masked art, Illustrator discards them]. We can retain some flexibility by grouping several layers at a time (land, parks and water; roads and trails; type can stay loose on top layers). In our current book, the frame is a rectangle with "rounded corners effect" which doesn't apply to Illustrator masks, so we have to expand the copied frame into a plain graphic with curve handles. For 69 maps, that means 69 or 138 masks. I'd rather not have to do a workaround for something that simply shouldn't happen!
The most promising workaround seems to be: consistently make the Illustrator artboard much bigger than the InDesign picture box, so the edge of the artboard never falls within the picture box. This the designer and I can work on together. Again, though, InDesign shouldn't display art that is legitimately hidden.
Anybody have any ideas? Thanks for your assistance!
P.S. In Apple Safari, why does this dialogue box show white type on a white background? Trying again in Firefox. Apologies for multiple posts.

Answer 1

Depending on which program is used to open the file here's what I get
Open with AICS3, It tells me that an new version was used but it will open. Everything is a single color (576) but in preview mode there is a clipping mask around the letter that is the wrong color.
Open in AICS4, There is no clipping mask, everything is one color (576)
Open in Acro 8 and 9, The file is two color with the odd colored letter
Do you have the original AI file to look at?