Thank you for the new logs and for taking the time to get them after a couple of hours! From your last reboot, it seems that the Shake is now transmitting good live data, with only a brief interruption:
In any case, from the logs, the booting process is fine, and the Shake bot starts and connects to the internet without issues. However, these lines in the logs, tell us that there is something going on between the boards and the sensors:
2023 242 23:25:32>> UUTBQUHIàQ U‹
2023 242 23:25:32>> Qªd…c UÒE]HªQHIàE®ÔEE†‹Q‹
2023 242 23:25:32>> 16247 268
2023 242 23:25:32>> No Data has been received from the MCU in 12 read attempts.It appears the MCU is not transmitting data. This is a fatal condition and should be investigated if this condition persists!
2023 242 23:25:32>> Data has been successfully received, fatal condition resolved.
As you can see, there are errors mixed with some ‘gibberish’ that cannot be successfully interpreted. My first thought would be to check and see if the power supply is delivering a stable voltage between 5.0 and 5.2V and a current of at least 2.5A at all times, as a decrease in power could lead to data services interruption. If the data interruptions continue to happen, and if you have another Pi power supply that you know is in working condition, please try to exchange the current one with that, and see if the Shake now properly works for longer periods.
A second check that you can do is to see if all the connections between the sensor, the blue Shake board, and the Pi board are still solid and free from dirt or any other element that could compromise transmission. As usual, if you decide to disassemble the Shake when doing this, please make sure you are using proper ESD (ElectroStatic Discharge) protection (such as gloves, etc.), as electronics do not like static electricity too much.
Other than this, please do continue to monitor the Shake behavior, and maybe check if the data interruption happen more or less at the same time of the day, or only during the weekend/weekday (and at what time), because it could also be that your local power grid is subject to temporary power levels drops that could cause what you are seeing.