State Timeline ignores end time in wide format despite correct data type (timestamp)

I’m using wide format for State Timeline - supplying two columns, one for start time, and one for end time, and State Timeline should allow that. Both columns ar passed as timestamps. The setting for merging stats is also turned off. So I followed the troubleshooting that I found elsewhere.

And yet the chart still merges one state with the next state, without leaving the gap between one end time and the beginning of next start time, as I show in the screenshot below.

I cannot see the error.

One guess I have is that there must be additional rows with null values, to represent the empty gaps between states, could that be the case?
Another guess is that it has something to do with infinity or json…

This is this wide data format I am trying to use: