Thinking Machines Lab, the AI startup founded by former OpenAI CTO Mira Murati, is facing what could turn into a full-blown employee exodus. The problem? Several staff members are now considering following three co-founders who just walked back through OpenAI's doors.

The Return Migration

Tech journalist Alex Heath broke the news on X Thursday, reporting that "More Thinking Machines employees are in talks to join the 3 founding members who just rejoined OpenAI." Those three founders are Barret Zoph, Luke Metz, and Sam Schoenholz. How many employees will ultimately make the jump remains unclear, but the discussions are actively happening.

Trouble Brewing Inside

The situation got messier this week when Zoph was fired. According to Heath's newsletter, at least a few employees resigned immediately after what sources described as a tense all-hands meeting about his departure. Not exactly a confidence-building moment.

Here's the bigger picture: Thinking Machines Lab has struggled to figure out what it actually wants to be. Despite pulling in a massive $2 billion seed round last year, the company has hit roadblocks trying to raise more cash at a valuation jump from $10 billion to $50 billion. Its sole product, Tinker, is an API for fine-tuning open-source AI models. The company hasn't trained a major foundation model yet, which raises questions about its competitive positioning in the crowded AI space.

Neither Thinking Machines Lab nor OpenAI responded to requests for comment.