Most of what you mentioned are known issues that Occipital is actively working on, but I’ll share my journey in case it helps you inch along while we wait for some fixes.
First, the application not seeing the sensor: While the frequency of this issue varies by person, I think it’s pretty ubiquitous within the Mk2 user group. It sounds like you are one of the lucky ones that this happens to almost every time. In my experience the best thing to do is launch the app, if/when it is not detecting the sensor unplug it live with the app open, plug it back in, and typically this will trigger recognition within the app. If, however, you have not only a lack of recognition, but a freeze as well (hard to tell the difference sometimes, but the detection shouldn’t take that long, if it does, bet on frozen) then I will unplug the device, kill the process, restart the process, and THEN plug in the sensor. This has a high success rate for me.
Note You mentioned the lights - this is a good indicator of whether or not your next attempt at reconnect will work. I have found that in the above process, if I plug in the sensor, and receive the Magenta flashes, it should then flash solid blue if an appropriate app is open. This is good. If, however, when you plug the sensor back in and it skips the Magenta, going straight to the solid blue flash, then I have found that it will not connect again, and is just a little bit away from telling you that it is out of power and needs to be charged. When noting this behavior as a leading indicator it has been 100% accurate for me and saved a lot of frustration from trying over and over. Lastly, the normal behavior when a compatible app is NOT open is what you noted in your post: Magenta Flashes at startup, then nothing until a compatible app is opened. Once they get the firmware fix out I hope this issue will go the way of the dodo bird.
Charging: The flashing blue means the sensor is charging, when it has completed charging it will turn a solid blue. The Red flashing I have recently experienced a few times as well, it’s undocumented so far, and I have been unable to reproduce it reliably for their support team. I have only seen it while charging, and I have seen the behavior of starting out flashing red, but swapping over to blue after some time, to finding it flashing red after a night’s charge. The latter went away when plugging the sensor back in again. In either case thus far it’s been a benign behavior, if I can reproduce it or find out what it means I’ll be sure to share as well.
Hope that helps get you along at least a little bit while we wait.