Hey guys, thanks for all the recommendations.
@Fireberd: I'm also on Win 10 1803. I'm running Cakewalk v24.04.1 build 31. I tried uninstalling, rebooting, then re-installing the Tascam driver but no go.
@Zargg: Cakewalk version is above (v24.04.1 build 31), Tascam driver is the most recent on their site (2.11), Cakewalk driver mode is set to ASIO. I see what you're saying about the device being occupied by another app - when I open the Windows Sounds settings the audio drops out in Cakewalk. Same thing happens when I hit the record button on my track.
@Cactus Music: My laptop only has USB 3 ports. Curios though, because it had been working great for over a year with this thing. And the driver install doesn't prompt for a device connection, it just runs through the wizard and closes. Device is always connected and powered on before launching Cakewalk. I can even see the volume level bouncing around in the Tascam UI for my chosen input. But Cakewalk still doesn't receive the audio.
It totally feels like a Cakewalk issue because the Tascam appears to be functioning fine and the audio drops out of Cakewalk as soon as I start messing with the PC sound devices or when I hit record. I think I'll completely uninstall and re-install Cakewalk next. Any other suggestions are more than welcome.