Engineering Vice President Jeremy Gordon is leaving Twitter, CNBC has learned.

The departure could bring fresh fuel to concerns that Twitter's internal politics are still not settled, as investors are looking for stability at the company. Gordon has been at the company for two years, and came to Twitter through an acquisition. Adam Kinney a four-year veteran who leads the company's Analytics group, is also leaving.

Gordon is known within Twitter to be a valuable contributor to the product development process. Gordon had been a director of mobile engineering until a year ago, when he was promoted. He became a vice president, with about 400 people reporting to him, in April. Kinney, a director-level engineer, is known among peers as a valuable role-player.

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Twitter confirmed the departures.

According to a source with knowledge of the matter, some engineers at Twitter are concerned that the company's product vision is not clear enough. Despite what CEO Dick Costolo told CNBC this week — "the team that I have in place and the strategy that we have, we love, and we all believe in it" — some in the engineering organization are not clear about where Costolo and engineering executive Alex Roetter are leading.

It's a critical time for Twitter's product and engineering teams to catch the vision. The company's financial results on Monday revealed that people still aren't coming to Twitter and staying at the rate that the company would like; monthly active users grew to 284 million, up 13 million from the quarter before. Costolo told investors on the earnings call that Twitter's "pace of execution" needs to increase so that the company can launch products and improve them faster: "I'm really talking about faster iteration from hypothesis, to prototyping against that hypothesis, to experimenting against that prototype, to launching against that experiment and then iterating across that cycle," he said.

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This would be just the latest in a series of reorganizations in the teams that build the Twitter product. In 2010, longtime product executive Jason Goldman left. In 2012, product VP Satya Patel left. In June, then-Chief Operating Officer Ali Rowghani left, and Costolo began having product and engineering report to him more directly.