@katejaiheelee the problem still exists with TwitterKit 3.0.4 and Twitter app 7.4
To fix it properly each app needs to specify a unique app URL scheme so that the Twitter app will be able to forward login data back to the correct one. A simple (and backward compatible solution) is to support URL scheme suffix. This way application 1 and 2 have different URL schemes and this problem will never happen again.
Facebook SDK does the same, so it’s a solid solution.
Related bug and solution discussed here
Please take this in consideration “quickly”. With iOS11 there is no other way of authenticate user that using TwitterKit and now it’s clearly broken.