So you get hangups when one Dell listens to another Dell? Are they genuine Dells or Rebadged? I've got one genuine dell and five rebadged Dells and four Genuine receivers so I'll try and test your problems on my setup. I have never noticed any hangups or flakiness at all while in listen mode using alpha 5.

Edit: Maybe I'm not having the flakiness because I'm using jrec while you're using ARM? Have you tried jrec? (yeah I know it's a *little* difficult to set up but it sure is stable).