Twice changes lost after committing and merging the branch

[Rod Barnes]

I'm using Visual Studio 2017 v13.3.0 (source control is disabled) and SourceTree v2.7.3.  Twice now, I've made changes, committed them, pushed them -- and then lost the changes in the process.  NOTE: A fetch does not fix this after it happens.  Nor does it happen all the time, only twice so far since the SourceTree update to 2.7.3.

The behavior is this:

1. In Visual Studio, make changes to the source.
2. Note that SourceTree indicates changes to the source.
3. Commit and push.
4. Go back to Visual Studio, and it complains about external changes to the source and wants to reload the solution.  NOTE: This has not previously been the case and it doesn't happen when everything "goes well".
5. After reloading the solution, all the changes are gone and the source is back to where it was before the commit.  However, SourceTree registers nothing different about the source; no indication of changes.  So, even though the code was changed, committed, and pushed, and now it is back to what it was, SourceTree doesn't recognize the change.
6. In Visual Studio, make the changes to the source again.
7. Note that SourceTree indicates changes to the source.  In fact, you can see it recognizes the exact same changes as before.

I'm not sure which is doing what here but I would expect SourceTree to recognize there have been changes if Visual Studio reloads the solution and everything is back to what it was.

NOTE: Since someone may ask, "Why use SourceTree when you have source control in Visual Studio?", it is because I work in many different tools and languages, even within the same project, and want to use a single tool to manage my source control.