A now-fixed Twitter location bug inadvertently let the app collect your location data under certain circumstances (via 9to5Mac).
Twitter Location Bug
The bug, which Twitter disclosed today in its Help Center, caused the app to collect and share iOS location data with a “trusted partner.” If you have multiple accounts in the app, and use the Precise Location feature for one account but not the other, the bug could’ve collected data for the other account anyway.
Specifically, if you used more than one account on Twitter for iOS and opted into using the precise location feature in one account, we may have accidentally collected location data when you were using any other account(s) on that same device for which you had not turned on the precise location feature.
Separately, we had intended to remove location data from the fields sent to a trusted partner during an advertising process known as real-time bidding. This removal of location did not happen as planned.
Twitter will contact you if your account was affected by the bug. If you have further questions you can contact Twitter’s Office of Data Protection.
[How to Secure Your Twitter Privacy Settings]
[iOS: How to Remove Location Data From Photos on Your iPhone]