When you enter a arena you stay in the queue for the others you're queued for, so if you went in as a 5 man group into cracked planet, when salvage operation shows up it times out in the background, meaning whoever is in there has to wait a minute for 5 people to time out before it moves onto the next people in the queue, if the next people are in a arena, or chose not to enter for any other reason, there is another minute without people joining.
Change 1: 10 seconds to respond with either 'join' or 'give me a minute' the second one gives you a 60 second timer to complete whatever you're doing.
Change 2: When you enter a arena, get automatically removed from any other queues you are in.
In the last 20 minutes I've been in a salvage operation that was 7 v 0 ...sigh. And worse that that I've just been in a cracked planet that was 6 v 4... it's supposed to be a 5 v 5 arena, wtf