I have issues with buffering when using my chromecast and the "Video& Tv Cast "app. Sometimes it works great, other times it buffers every 1-3 minutes. I thought it was due to several wi-fi signals in the neighborhood so I purchased a new router that went to the 5ghz frequency which shouldn’t be interfering. It seemed to fix the problem until last night. I confirmed that it’s not the tablo, because I could watch my recordings on my iphone or in my PC browser just fine. The problem only occurs when casting (from iphone or chrome on my PC).
I also have the sporadic problem you are describing, and I also am leaning toward the Chromecast as the culprit. One day I can run it off my PC for 3 hours with no problems, and the next day it may run for 20 minutes and then start the stop/start/stop/start issue. If I let it go long enough Chromecast will either lock up or disconnect. Disconnecting and reconnecting Chromecast sometimes helps but not always. Just as you describe, I can stop casting from my PC and immediatly the streaming video works fine there. I have a similar issue when casting from iPods using TV Cast browser. I have found that if I stop casting from the PC or iPod and use my Android phone, the problem seems to go away or at least happen much less frequently.
I’m hoping new versions of the Tablo apps will be coming out soon. I haven’t received an update in a while.
Note: I forgot to mention that if I am browsing with Chrome on the PC while one of the tabs was used to cast Tablo, I have many more issues than when the PC is devoted only to Tablo.