Fujifilm just recently updated the firmware on the X-T50 to version 1.01, but there’s been a small and unusual “bug” identified, which only affects certain models. The 1.01 firmware fixes some minor and rare issues; however, the firmware update itself has one issue.
The problem is a weird one: on only certain X-T50 cameras, you cannot update the firmware. That’s the bug. On certain models, you’re “stuck” with version 1.00. That’s no big deal, because version 1.00 isn’t bad whatsoever; version 1.01 was basically only a minor-bug-fix type update. I think the issue must actually be with version 1.00 and not 1.01, but it will all get sorted out soon enough, I’m sure, so no worries.

Specifically, the cameras affected are the silver models (not the black or grey) that were sold with the new kit zoom lens (apparently not the ones sold with 15-45mm lens or body-only) that have these serial numbers: 4BA24662 to 4BA26561, 4BA30592 to 4BA30661, 4BA34838 to 4BA35137, 4BA35678 to 4BA35857, and 4BA37468 to 4BA37687. Fujifilm was quick to acknowledge and apologize for the issue, and they are working on a solution right now.
The Fujifilm X-T50 that’s sitting on my desk in front of me is black, so I’m not affected, personally. However, if I were affected, I wouldn’t worry much. Also, it’s always a good idea to wait at least a few days—if not a few weeks—to update the firmware, unless it is one that fixes a major bug. From my experience with apps, when you fix the coding for something, something else seemingly unrelated can be affected by it; that functionality (whatever it is) wasn’t thoroughly tested because there was no expectation that it would perform any differently than it had before. So waiting a few days or longer before updating is a good rule of thumb that can save you some heartache later.
See also:
Fujifilm X-T50 — The “Digital Film” Camera — But who is it for?
Fujifilm X-T50 Film Dial Settings + 14 New Film Simulation Recipes
Fujifilm X-T50 + Fujinon 23mm F/2 = Interchangeable-Lens Fujifilm X100VI??