I recently purchased an 1882 Mexican 8 reales coin at a flea market. The coin had obviously been cleaned but actually has pretty nice detail. A quick ring check to my ear confirmed that it was silver so I bought it. Once I got home I had a closer look and noticed that LIBERTAD is actually spelled LIBEFTAD with an "F" on the coin. Is this a known error? A quick check has confirmed that the coin is indeed silver and it weighs a fraction over 27 grams. Any got any thoughts in this? Is it a mint error? A contemporary fake? Apologies for the bad picture....
One thing you shouldn't do is hold your coins when taking a picture. Set it down a sheet of paper and use a tripod for better pictures. (I know that's not what you wanted to know, but I have no idea what that could be, so I will give you the advice I have.)