@mashina I have made an update after being able to replicate the problem you described.
Issue it seems was an error 500 occuring on line 329 of the taskingelement.class.php element because it couldn’t find a relevant imaging log.
I’ve added code that seems to be able to address this though not sure what is actually wrong otherwise. WIth the patch I made things seem to complete okay so I think it’d work good for uni and multicast tasks if you’d be willing to update and test?