Unexpected error when running MSTest unit tests after upgrading to Resharper 2017.3.2

Yesterday I updated from VS 2017 15.3.x to VS 2017 15.5.6 and from Resharper 2017.2.x to Resharper 2017.3.2. Please note that I did *not* modify my <solution-name>.sln.DotSettings file in the process.

After upgrading, when I first attempted to run my MSTest unit tests with Resharper, I received the "Inconclusive: Test not run" message for *all* of the unit tests in my solution. I looked at the execution log and saw this error message for each of my test projects:

"The settings file <C:\dev\git\messaging-dotnet\Local.runsettings>, specified in the MSTestAdapter settings, is not available..." (There was a bit more at the end but you get my point.)

The first thing I did was look at my Resharper Options for MSTest and, sure enough, the Select Test Settings File field was set to Local.runsettings and my .DotSettings file contained this line, though I never recall ever explicitly setting that field:

<s:String x:Key="/Default/Environment/UnitTesting/MsTestProvider/RunConfigurationFilename/@EntryValue">Local.runsettings</s:String>

Since we keep our .DotSettings file in our source repository, I looked back at the history of the .DotSettings file and this entry has always existed. However, we've never had our tests fail to execute due to the absence of the referenced Local.runsettings file before -- not until the upgrade to 2017.3.2.

Why, starting with 2017.3.2, does Resharper fail to run MSTest unit tests when the Local.runsettings file is referenced in the .DotSettings file but does not exist on the file system?

It makes sense to me that it would fail, but I don't understand why it only started failing after the upgrade.