Right now I'm pretty confused. What did I miss? In retrospect, it seems very odd to me that switching the lines sending velocity ad note in arp would have any effect. I would expect those to lines to happen "simultaneously" at least from interconnected pd-objects point of view.
Personally I consider this to be a somewhat fundamental problem in Pd: There is actually no way, looking at an outlet with several lines coming out of it, to determine what order they will trigger. It actually depends on what order you connected them in. To me this is important information that is simply _missing_ in Pd's graphical representation.
Note that this is not true in Max/MSP: messages are always triggered from right to left.
It would be nice to fix it, but unfortunately doing so would probably affect backwards-compatibility with people's patches. Anyways, if you have something which absolutely depends on the order in which a message is sent out multiple connections, insert the [t] object to re-trigger the same message several times, and make one connection per outlet. Messages will be ordered from right to left.
My patches are just full of triggers like this.
Steve