My manager works in a different city and asks for updates in a group chat several times a day. Me, and one other contractor were hired a couple months ago to work on a specific project. There is one other person (call him Bob) who sits across from me. Bob is sort of the "unofficial boss/go to guy" because he's been working on the project since the beginning and my official manager said I can ask him questions.
Basically the project is migrating a web app from one system to another. There are some sections have pages that are very similar to each other so I duplicate a template instead of starting from scratch. I was asked to assist the other contractor on a section he was working on. I asked him which portion I should do, and I asked if I could use the already completed pages of the portion as a template. He said yes and I've got this saved in the chat.
Unfortunately none of the pages that had appeared to be done, were actually done (or were done incorrectly) so basically I thought the section was done, told the manager that I was just double checking things, and keep finding things that were done wrong but the expectation wasn't clearly communicated to me.
Should I just tell the manager it's not as close to being finished as I thought it was, or should I tell him that the other guy said his section was done and I could use it as a template? I kind of feel like I'm throwing the other guy under the bus but it is true.
I don't believe in getting people "in trouble" or "getting mad at them" in the workplace, but I sometimes find this incompatible when something goes wrong and the manager asks for an explanation.
Additionally my understanding was I'd be helping him with his section, but aside from the couple of (incomplete) pages he did at the beginning, I did the whole thing.
Another thing was that all the other sections had a feature that this section didn't. I told Bob that it was going faster because it didn't have this feature. A lot latter Bob told me this feature was needed though he probably knew I hadn't been including it because I had mentioned it to him several times as an aside.
This is really stressful as the project is behind schedule and I really care about it. I'm feeling sick and may have to miss work tomorrow and I had told the manager it would definitely be done by noon and when I found all the other problems I told my coworker I'd come in early to get it fixed.
The manager prefers everyone use the group chat, but since I don't want to create ill feelings with the coworkers should I take the initiative to send him a private message, or only if he brings it up first that there's a delay?