“Wtf is X” was trending Monday morning as the Twitter app logo on devices everywhere suddenly changed from the blue bird to a black-and-white X.

Many of the social media platform’s users have criticized the company’s flashy new logo as the app rebrands from Twitter to X. But more disastrous than the mad dash to rebrand the app is the company’s seemingly impulsive move to change the signage on its headquarters in San Francisco without proper permits. While the app’s users have joked that its digital rebrand has been harmlessly sloppy—for example, the app still prompts users to “search Twitter” and “tweet,” rather than post Xs on desktop—the San Francisco Department of Building Inspection has raised more serious concerns offline. The city is currently investigating the Twitter building’s signage changes, some of which have already been deemed unsafe.