State timeline doesn't merge values

I created a statetimeline panel with analog data (ranging from 0 to 5000).
I wanted to create value mappings using the new range condition:

I menenged thanks to this forum topic to successfully indicate if the graph should show OFF, OK or OK - Working.

But now when I hover my mouse over the statetimeline graph the values are not merged - even though I set the option Merge equal consecutive values to True:

It shows that duration was 19 seconds even though it clearly was in ON state for more then 2 minutes.

I have a postgresql datasource and running this query:

SELECT total_aprt_power as "TAP", time
FROM shelly_data
WHERE $__timeFilter(time)

What can I do so that the analog values would be merged? Is it even possible with the statetimeline panel right now?