None of the mods on this site will give you the straight up honest answer which is that black lines obscuring the screen is a known, non fixable issue.
Once it starts the issue will only progress over the next few months until the screen is unreadable and the device is for all intents unusable.
If your device is within warranty apply for a refund before this runs out.
Fitbit may offer you a discount against one of their other devices. Given their lack of honesty about existing issues and their habbit of releasing hardware which they know does not work as advertised then promising software update fixes that never happen you may want to think hard before accepting this instead of an outright refund.
Community Moderator Alumni are previous members of the Moderation Team, which ensures conversations are friendly, factual, and on-topic. Moderators are here to answer questions, escalate bugs, and make sure your voice is heard by the larger Fitbit team. Learn more
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