SourceTree user interface is constantly out of date and does not recognise changes made on the filing system - this affects source files edited via the editor as well as any changes made via git command line.
The net effect is that it is ridiculously easy to make a commit (and subsequent pull request) whcih is incomplete because SourceTree has not noticed that there are additional files to be added to the index.
Sometimes, you can persuade SourceTree to update by switching between views, but sometimes the only way is to close it and restart.
These problems usually occur even if the only tools which use git in that repo is SourceTree and the only other changes are text changes by my IDE.
Sometimes, even if I use SourceTree to commit and change branches, the Repository Browser will show the wrong branch - i.e. SourceTree does not recognise changes that SourceTree made moments before.
I have reported this on the forum back in November 2017 - so three months ago, and despite several updates the problem persists. Forum post with screen shots here: https://community.atlassian.com/t5/Sourcetree-questions/SourceTree-UI-is-constantly-out-of-date/qaq-p/669649#M18206
I've marked this as Major severity because it makes SourceTree unusuable and drives users to switch to other products.