Streaming music startup Spotify has confirmed that its CTO has left, effective today. Andreas Ehn tweeted about his departure this morning, in a move which has taken observers by surprise. The company is currently prepping a big launch in the U.S., a watershed which would normally suggest that this is a moment to have all hands on deck. Losing your CTO right now is probably not the best timing, to put it mildly.

However, a Spotify spokesperson has told me that they’d “like to thank Andreas for all his brilliant work” and “everybody at Spotify wishes him well in the future as he seeks out new and, no doubt, extraordinarily complex challenges!” I’m sure this isn’t meant to sound back-handed but Ehn’s tweets paint a slightly less rosy picture.