I have the most recent version of Welkin Suite installed.
I created a new sandbox and linked up Welkin Suite to it. When I went to create a new test suite by clicking "TEST" in the main nav bar and clicked on "Test Suites Manager" I recieved an error to which I cannot recreate and sadly I did not capture it. I had something to do with a "Field" cannot be (null). I figured this meant that there were no test suites available since its a new org and none have been created yet. The problem is that it was bugged out after the error message and continued to the loading test suites page and hung. At this point it would not let me create a test suite either. So, I went into the dev console for the org manually and created a test suite. When I repeat the process above to access the Test Suites Manager it works perfectly fine as usual.
The error message recieved did not imply there were no test suites available and should have an error message to match that null value. I have done this before with orgs that dont have test suites already and it worked fine so, it must be a recent bug. I would think that if it errored out it finding existing test suites it would still at least allow me to create a new one.
Hot fix - Create at least one test suite through salesforce UI, the developer console, first before accessing test suites manager through welkin suite.