I’ve seen the garbage collector go nuts, at times, from what seemed like string manipulation. Instead of the font, perhaps it’s the strings? I don’t think it was actually losing the memory, rather memory fragmentation issues from lots of little allocations. I got the feeling that the allocation strategy wasn’t very efficient.
It’s not overly helpful, other than suggesting that you may be able to do something with the strings to work within existing memory and avoid the string copy, which typically causes an allocation.... And then see if that helps. My issue involved a Debug.Log(), and so all I had to do was remove it and my memory issues went away. I doubt it’s that easy for you. :)