We're working on implementing a way for the K/V server response to trigger an Interest Group update instead of waiting for the 24 hours to elapse. (Discussed in #729 (comment) and later in that thread, although the discussion there has other aspects that aren't about updating speed.)

Will that address your concern? I think triggering an update from the K/V response seems better than from the contextual response, since in the contextual request you deliberately don't have any idea what IGs are on the device.

#729 (comment) partially address the requirements to solve this problem, and that solution only works for IGs eligible for real time K/V server requests.

Also with that solution an IG not eligible for real time request has to wait for about 24 hr to get fixed by next daily update.
This solution does not provide a way to trigger update to all IGs

While this ask is to provide a signal in contextual response(in perBuyerSignals or similar object) to refresh all IGs, that will eliminate dependency on IG eligibility or real time K/V server response.

What "IG eligibility" dependency are you worried about?

It is deliberate that the only IGs that get a chance to update is ones that are invited to participate in an auction on the current page. I'm not sure whether your goal fits within that constraint.

As per my understanding an empty IG does not participate in auction (let me know if this is not correct).
An IG will not participate in auction when a bad update wipes out all ads in it, hence no option to update them via realtime K/V request/response.

Also proposal #729 (comment) is per IG, while via contextual signals we can update all IGs irrespective of auction eligibility.

I was under the impression that an IG with no ads, but at least biddingLogicURL, is eligible for, but of course could not place a bid in, an auction. If it has an updateURL then after that auction it could be updated. Lacking that, then it really is "empty" or perhaps "inert."

One potential solution is to introduce a timestamp-based mechanism for invalidating IGs. The buyer could specify a timestamp in contextual response, and Chrome would refresh all IGs if their last refresh occurred before that time.

This timestamp approach would restrict forced refreshes to a single instance per browser, preventing IG refreshes with every contextual response.