Yes, it smells
Be sure to not let it spill anywhere. I cap the fresh bottle before I leave the kitchen and I cap the old bottle before I return to the kitchen to dump it, just in case I should trip over the cat.
Be sure to never let the tank water siphon down the tubing if the bottle is located below the tank. I set the bottle and bubble counter/scrubber on top of the hood before I change out bottles and leave it there until it is going well.
Even so, with the water pump that powers the reactor in the bigger tank, on occasion it has managed to spill out even above the tank. Even the bubble counter water smells bad. I now change it with every bottle of yeast. Makes me wonder what has gotten into the bubble counter.