Hey there as a workaround if someone who is affected by this issue can add an additional command line argument to their Overwatch startup we want to see if this fixes the issue for you.
Note this is an advanced startup line, you’ll want to clear this line after testing. Changing startup options can lead to odd problems.
To set the command line, in the Blizzard Desktop client with Overwatch selected, choose Options > Game Settings. Find the Overwatch entry in the list, click the Additional command line arguments checkbox. In the textbox there add:
--tank_WorkerThreadCount 1