I can happily report that time-shifting and recording work as expected in 12.0.226
1. The flickering issue mentioned above still occurs episodically (but regularly) during playback and everytime while zooming.
2. I have also noticed that every now and then MC becomes unresponsive for up to 10 seconds, and this has happened during playback and when navigating TV options. I am confident that i could reproduce this again if a log would be helpful.
Thanks again
PS looks like you can add Dell USB Analog TV Tuner to the list of supported devices.