I am going to ask the AM about the lagging conversions postbacks and the PropellerAds representative how it effects the CPA Goal campaign on the next Monday but I can't wait so maybe somebody else has some insights.

As you can see, the conversions are coming back 3-4 hours after the visit. I don't think it is normal for a simple conversion flow like SOI like in this example.
This is how the traffic sent by the CPAg campaign looked on the hourly basis.

The 17 conversions for the 13:00-13:59 hour has been posted back with a delay of 3-4 hours, so about the 16:00-16:59. I am still running the campaign. The volume has really dropped.
So could it be that the CPA Goal campaign can't work properly with the delayed postbacks? Or does it not effect the optimization at all?
Let's say a placement has been stopped by the algorithm because it has not received any conversions but the conversions are coming after 3 hours and the placement is actually profitable. Will the algo resume the placement?
Or maybe the offer sucks.... But it shouldn't because the AM and @jaybot said that offer converts like crazy....
Btw, tested the SmartCPM, the ROI is horrible as well. About -70% ROI and EDP of placements just above the $10
What is the offer and with which network?
PropellerAds lagging is a huge problem. It affects on our decision
Some offers just send conversions later, some affiliate networks also send conversion data only each hour or every 15 minutes or so.
In the end it doesn´t have much impact on the CPA Goal campaigns.
When a placement doesn´t convert good enough it will receive less traffic or no traffic at all anymore.
When then conversion data comes in later and gets posted to Propeller Ads then the performance for the affected placements increases again and traffic can start flowing again.