Hey Alexban,
You edited your post after my latest reply. I am 100% sure you wrote initially that after a bleed trip off you select the 'bleed' switch to off. You changed that to 'pack' switch. My reply was partly referring to that. Makes me look a bit like a fool don't you think so ? Editing is ment for grammar corrections, not to change the contents of your post.
Were did I write that after a eng. bleed trip off light with the bleed switch on, bleed pressure is still available from that engine?
Referring to my theory about the bleed switch position as a back up (isol. valve sw. in auto). Indeed it is just a theory. For the rest
I am fully aware again (as I already wrote) about the isol. valve position with the switch in auto in relation to eng. bleed switch or pack switch postion.