So I got my manual transmission fluid replaced at a Honda dealer and the tech said that my left axle seal is leaking. Is this a common problem for TL's? I am only at 68k miles.

The thing is, I had my CV joints replaced under powertrain warranty at an Acura dealer. Are these 2 related?

 

Yes. They should have replaced the seals when taking the axles off or any work being done there. Take it back to the dealer.

 

Very rarely do the axle seals leak. Not stating that yours isn't, but I'd clean up the area and make certain it was the axle seal and not from between the trans and engine from the vent discharge. If the trans isn't checked and filled in the correct manner and is overfilled, the excess will come out the vent and naturally be seen.