This happened a few years ago. We started this new project that was estimated to take 3 devs around 5 months to complete. We had a meeting where the client, the project manager, me and two other devs were present. When the client asked if we were still on track to complete the project by the end of September, the PM just said “yeah we are totally on track, no worries”.
Me and the other devs looked us straight in the eyes and nonverbally agreed that this guy has to be sniffing glue or something. For context: it was August.
After the meeting we immediately raised our concerns with him and our boss. The deadline was shifted and a freelancer was hired to assist. The PM quit shortly after and a way more competent guy took over. But the damage was already done.
In the end we finished that project in February or March the following year. Client was still happy but this shit triggered a whole clusterfuck of a year. Other projects were lagging behind because of this and we had to push out project after project that had accumulated in our backlog.