Oil Leak

Around 8K miles ago I had the UIM replaced on my 1997 LeSabre (176K miles), I also had the lower intake gaskets replaced. Now, I am starting to see oil leaking out on the block (driver side) this in turn is getting on the exhaust. The only place I can see where the oil is leaking is from under the lower intake and block mating surface, it is only a small amount of oil, more like a seepage.
I used Felpro gaskets for this job. I have seen lots of gasket replacements on these engines and never heard of an oil leak before. I applied gasket sealer to each corner of the lower intake and all was well until recently.
Anyone have a clue on what may have happened here? I`m going to have to redo everything, should I go with GM replacement gaskets this time?

Try retorquing everything first.