Prebid.js: CMP timeout scenario: auction without consent not running despite GDPR Enforcement Module rules

Type of issue

Bug or documentation issue

Description

We need the auction to run even when the CMP banner stays open, relying on the “basic ads” legitimate interest. In Prebid 3 this was working with the allowAuctionWithoutConsent. In Prebid 4 and 5 I can’t find a way to enable the same behavior. I’ve read that it should be possible by using the GDPR Enforcement module, so I have included it’s configuration:

            defaultGdprScope: true,
            rules: [{
              purpose: 'storage',
              enforcePurpose: false,
              enforceVendor: false
            }, {
              purpose: 'basicAds',
              enforcePurpose: false,
              enforceVendor: false
            }]

It made no difference, with CMP banner open the Prebid triggers cmpFailed and stops the auction. The enforcement module code wasn’t even touched, from my debugging.

Relevant logs:

• Prebid INFO: Received a response from CMP t {cmpId: 7, cmpVersion: 1, gdprApplies: true, tcfPolicyVersion: 2, eventStatus: “cmpuishown”, … …long delay
• Prebid ERROR: CMP workflow exceeded timeout threshold. Canceling auction as per consentManagement config. undefined

CMP returns event from TCF API, it gets processed with this function:

  function v2CmpResponseCallback(tcfData, success) {
    utils.logInfo('Received a response from CMP', tcfData);
    if (success) {
      if (tcfData.gdprApplies === false || tcfData.eventStatus === 'tcloaded' || tcfData.eventStatus === 'useractioncomplete') {
        cmpSuccess(tcfData, hookConfig);
      }
 ...

the second condition leaves it hanging, since eventStatus is cmpuishown. It doesn’t look for the enforcement settings. Is this by design, or am I missing something?

Steps to reproduce

1. Load the page with no TCFv2 consent in cookies/localStorage.
2. Prebid should wait for CMP timeout but still start auction, when purpose: 'basicAds', enforcePurpose: false, is in config.

Test page

https://playground.cpex.cz/headerbidding

Expected results

Auction to run

Actual results

Auction not running

Platform details

Prebid.js v5.2.0 (v4 behaves the same) MacOS, Chrome

Other information

None