I made a clumpsy solution to solve the problem ... trigger bang doesn't work (I tried that first, of course!)

well, there is a "mistakes" in the jb.iter you could fix so you don't have to do any workarounds. on the left is a "new" version of jb.iter that uses less objects and is a bit cleaner. on the right is the "old" version with only the fix. the thing that was changed is the way the carry flag from the [counter] object is handled. introducing timing with [delay 0] seems wrong to me. I use [sel 1] instead.

Also, in my version if it is used as an abstraction you can add "@mode 1" so that a new incoming list doesn't interrupt the old list from iterating. When a new list comes in it is ignored if there is an iteration in progress...

Hope this is helpful.