As of March 27, Googlers claim that a problem preventing Pixel 2 users from receiving either MMS or group messages has been fixed. That should mean no more error messages or failed downloads of group or picture messages. However, that doesn't seem to be the case for everybody involved and several users are still complaining that the issue is ongoing. Google never really clarified what the problem was but the responses to the thread seem to indicate that it was solved with a simple software fix installed via an update to one or two apps. Meanwhile, it may be recommendable that users still experiencing the issue go through the steps required to clear the data and cache of their messaging apps. That will ensure that there aren't any remnants of buggy code still being stored and called forward.
If that doesn't resolve the issue, then it should definitely be reported to Google since that might indicate the problem was not fully resolved at all. Conversely, it may mean that there are additional steps that need to be taken in order to get the issue resolved completely. In either case, that would mean that Google still has quite a bit of work to do. Maintaining consumer confidence is absolutely vital to mobile manufacturers and not resolving the messaging problem in question could have a palpable negative impact on the Pixel lineup going forward.
Google is not the only smartphone vendor that has recently been dealing with messaging issues. Late last year, Samsung's Galaxy S8 family of devices started having a similar issue but pertaining only to text messages. It goes without saying that no smartphone or handset manufacturer is without its quirks or issues. With that said, problems with text messaging and related messaging services present a unique conundrum for those companies. Those kinds of functions are something that every smartphone should arguably do well without any extra work or problems, being among the primary purpose of such devices. Google has yet to communicate whether it's still looking into the problem and the latest reports claiming the new patches failed to resolve it for some users.