I had my front brakes changed and brake oil changed as well.
No leak coming from the reservoir however I hear a squeak that sounds like it's coming from the reservoir when I pull the brake lever.
Bike stops fine and no oil leak.
You are moving fluid when you pull the lever. If you had coffin type reservoirs - you'll see a jet of fluid shoot straight up if you were to pull the lever while the cover is removed.
So you're probably just hearing that little bit of fluid transfer going on.
Ah yes, thanks, makes sense.