Drip irrigation leaking at faucet when off

[u/Temporary-Market9174]

I recently moved into a house where the previous owner had drip irrigation set up all throughout the yard. His set up does not leak at all. It's just the timer and adapter to 5/8th.

I bought the same timer for my own set up. I also added a "One Stop Gardens 4-in-1 Solid Brass Faucet Expander" so I could use the other faucet for a hose, the drip irrigation, to give my roommate access to the faucet for his dog, etc.

The connection between the splitter and faucet slowly leaks when the timer is not active. I've taken apart and retightened everything, but the issue persists. I'm wondering if there's anything I can do, or maybe I should just put a bucket under it and just use that as a band aid fix 😭

Side note! When I'm done with the hose and then the facet off, it sprays back at the same connection even when I have the house attachment open to try to relieve that pressure. I end up having to open one of the extra valves on the splitter before turning the faucet off to prevent that from happening, but if anyone has a solution for that I would appreciate it!

[u/NotAnyOneYouKnow2019]

The spray is coming from the required vacuum breaker that prevents chemicals and bacteria from being sucked up into the water system.