@space_skate I thought it was just my machine. After restarting TF2 several times, and then rebooting my machine, it seems the problem is on the TF2 side.
My new @Acer notebook was dead-on-arrival a month ago. At @Acer's request, I returned the notebook without the power adapter. Now they refuse to replace the unit unless I return the power adapter too. Seriously? I've been waiting a month, and they quibble over a power adapter?
Very disappointed with Boost Mobile's customer service. Wife and I have been with them for years, but it looks like it's time to find another provider.