I always use hose-clamps or zip-ties on rubber hoses, even if there's not much pressure of vacuum inside them. I've found sometimes, if they get pulled or twisted just right, they may develop gap with fitting and leak.
In your case, by disconnecting and re-connecting all hoses, you may have repaired tiny leak somewhere, even though all hoses were still connected the same. Don't think you're going insane, there's always some exception that throws monkey-wrench into works!
