In my game last night as Songhai, my capital had 696/700 great person points for an artist, and 693/700 for an engineer. I was getting 7/turn for artists and 15/turn for engineers. I had a Garden, as well as all SPs and wonders effecting GP generation rate. All my artist points were coming from Wonders. My engineer points were coming from both specialists and wonders. Additionally I was generating scientist points. I end turn figuring I'll get one or the other. But to my surprise and delight, I get both in my capital and both had their GP points reset to 0/900. Unfortunately I didn't take a screenshot and forgot to save. This seems to be a potentially nasty exploit. If it can be done in more than 1 city at once, it's theoretically possible to pop out a ton of 0/100 scientists or engineers in one turn and then have it reset to 0/1000 or something. Even if it can only be done in one city, you could still pop out a merchant, scientist, engineer, and artist without paying the extra points you should.