Prebid not rendering winning bid - prebid.js

Question

I was trying to setup prebid. I am able to receive bids, however the winning bid is not picked or the respective line item is not triggered, the ad of the bidder is not displayed. Instead it goes back to a fallback line items I created for $0.00 . The prebid console stops at Attempting to set key value for slot XXXX and then nothing, no winners, no render ad as shown in the below link
Look at the following image
Here hb_pb value is 0.40. But the respective line item is not selected even though there are line items with hb_pb of 0.36, 0.39 etc.
In the delivery diagnostics, I don't see the hb_pb request going to dfp. I am not sure why the case is. Please check the image. Here is my prebid code.
var PREBID_TIMEOUT = 1000;
var adUnits = [{
code: 'XXXX',
sizes: [
[300, 250]
],
bids: [{
bidder: 'XXXX',
params: {
id: YYYYY
}
}, {
bidder: 'XXXXX',
params: {
placementId: 'YYYYY'
}
}]
}];
var pbjs = pbjs || {};
pbjs.que = pbjs.que || [];
var googletag = googletag || {};
googletag.cmd = googletag.cmd || [];
googletag.cmd.push(function() {
googletag.pubads().disableInitialLoad();
});
pbjs.que.push(function() {
pbjs.aliasBidder('XXX', 'YYY');
pbjs.addAdUnits(adUnits);
pbjs.requestBids({
bidsBackHandler: sendAdserverRequest
});
});
function sendAdserverRequest() {
if (pbjs.adserverRequestSent) return;
pbjs.adserverRequestSent = true;
googletag.cmd.push(function() {
pbjs.que.push(function() {
pbjs.setTargetingForGPTAsync();
googletag.pubads().refresh();
});
});
}
setTimeout(function() {
sendAdserverRequest();
}, PREBID_TIMEOUT);
(function() {
var gads = document.createElement('script');
gads.async = true;
gads.type = 'text/javascript';
var useSSL = 'https:' == document.location.protocol;
gads.src = (useSSL ? 'https:' : 'http:') +
'//www.googletagservices.com/tag/js/gpt.js';
var node = document.getElementsByTagName('script')[0];
node.parentNode.insertBefore(gads, node);
})();
googletag.cmd.push(function() {
googletag.defineSlot('/XXXXX/YYYY, [300, 250], 'XXXXXXX').addService(googletag.pubads());
googletag.pubads().enableSingleRequest();
googletag.enableServices();
});

Answer 1

Issue here is that DFP is rendering the ad before prebid sets the key values OR something in your code is overwriting prebid key values
(DFPs setTargetting overwrites anything that's already on a slot)
I’d verify that you have DFPs disableInitalLoad set, and/or recall pbjs.setTargetingForGPTAsyc() just before your googletag.pubads().refresh()’s