Quizmaker sometime passes unknown (bad) characters in quiz data

I have not been able to figure out a pattern as to why I occasionally get students with a certain pattern of corrupt data in their quizmaker (AICC) LMS data. When I look at the data being passed inevitably I see a pattern of 3 sets of 2 bad characters (��) buried in the quiz data.

I found an explanation for the character itself on this page: http://en.wikipedia.org/wiki/Specials_(Unicode_block)

The diamond with a questions mark is a  replacement character used to replace an unknown or unrepresentable character.

The questions are:

1) Does anyone know what the characters are supposed to be?

2) Does anyone know what circumstances might cause a browser to throw these characters. 

This doesn't happen in one particular lesson. It doesn't happen all the time. For a student that it does happen to, it doesn't happen all the time.

It is extremely random as far as I can tell but there are always 3 sets of 2 diamond with questions marks.

Am using Studio 9 still. 

For example: 

viewed=1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43|lastviewedslide=42|42#1##,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,15,3#1#97aebb54-bb4a-470e-afb9-07f9ab09991d=250~243~233236244247242245241243238239246237210011~3441~31411110001010101010101010101001001001001001001001001001001001001001001001001001001001001001001001101001010110110110110110110110110110110110100102102102102100018310002��~2365fecac8a-53ae-4af0-bd45-8b44947406ce02��2��000000000000000000000000000000000000000000000000000000000000000000000107neutral212000107neutral11117correct11117correct11117correct11117correct11117correct11117correct11117correct11117correct11117correct11117correct110000000~3970000000000000000000000000000000000000~229~2181n11~2100101n448766200200~284~2201c11~21213111c511750~256~2101723031240~21017230316409162302840~21137230320411200~283~2191c11~21114111c43929~256~2101723031470~2101723031870~211372303107119162302670200~284~2201c11~21213111c566756~256~21017230310709162302670~21137230318611~21017230314602000~269~2191c11~21114111c49240~2429062302670~21107230314711~2100723031070200~270~2201c11~21213111c511000~242~21007230310709062302670~21107230314711200~269~2191c11~21113111c48633~2429062302670~2100723031070~21107230314711200~273~2201c11~21215111c513505~245~2100623028411~2100723031640~2100723031240200~270~2201c11~21215111c513551~242~211072303146119062302670~2100723031070200~283~2191c11~21116111c43083~256~21137230314711~21017230318709162302670~2101723031070200~284~2201c11~21214111c511627~256~21007230310609062302670~21107230314511~21007230318502000~24131i0~233200200200200200200200200200200200~24131i0~233200200200200200200200200200200200~232~226560000~216000000000010110000,#-1