Is there a limit for links (footnotes) pointing to a single html file?

Hi, folks.

First of all: please forgive me for my poor English. I'm from Brazil.

PROBLEM #1:

I've been producing e-books in the EPUB3 format for a while now. I've been using pop-up footnotes in those books without any problems until now. I place all my notes in a non-linear HTML file, as recommended, to keep compatibility with older versions of iBooks (that doesn't support HTML5's <aside> element).

Recently, I've encountered a problem when testing one specific book: the footnotes wouldn't work. When you click the number referring to the note, it turns gray (instead of orange, as usual) and iBooks stops responding for a while. Of course I revised note by note, looking for some markup error in the code, or something like that. There was no error. Also, the footnotes were working fine in other app's (Readium, Azardi, Calibre, etc.).

Well, after a lot of testing and not finding the problem, I've started testing the links (cumulatively), increasing one by one, when I finally came to the an apparent answer: there is a limitation in the number of links pointing to a single html file. The apparent limit is 33. When that number is exceeded, the error occurs. The solution I found was to separate my notes in two html files, since I had about 52 footnotes distributed along the book.

The way I see, it looks like a bug in iBooks, since there is no information about that limit in the EPUB3 specs or in the iBooks Asset Guide (5.2.2).

Does anybody here know anything about this issue? Am I posting this in the correct place? If not, where should I address this problem?

PROBLEM #2:

Still about the footnotes. There is another fact that seems to be a bug. One particular note ended up* on the first line of the page and it doesn't work. First, I thought it was some error in the code and I went checking. But the code was just like the others. Then, I tried this: I changed the font-size, on iBooks, so the footnote jumped to another line; then, just like magic, the footnote started to work!

It seems to me like the pop-up couldn't get enough space to show up. When it dropped just a little bit below (when the font-size was changed), then it worked. Did anybody ever faced this same problem? Is this really a bug? Is there any workaround?

Well, thanks in advance!

*Its position was determined by the natural flow of the content in that page.