You've managed to put a timeseries object into a table as a cell. To do anything with it, you've got to dereference it back to the inherent timeseries.
In other words, "Don't do that!"
Work with the timerseries as it is; the timeseries object is a real oddball thingie -- it is quite cumbersome and not well supported in continuing development in that there are no methods like read/writetable that work with it.
To convert it to a real timetable, try some variation on
where you get the time information and the data from the timetable and put it into something more usable.
The events that may be with the timeseries will have to be dealt with in some other fashion -- I've never had a case of my own nor found one in all the responses to Q? here of the forum that I could not more easily solve with other tools than the timeseries, so I don't know all the ins and outs of it, but it always was limiting in some way for any problem I was ever faced with.
The file is too big to download practically here in available time...but I'm sure some variant of the above will get you where you need.