Table history query some times return strange result

I setup history for a tag with 1 min scan class and increment it in gateway script every 1 sec in gateway version 7.9.10/11.
When I try to get min, max or range result, depend on selected time range it get strange wrong value. for example in attach image I get 414 for range,min and max query in selected range!!!
when I change time slider to 10:50(which is the time for future) the result is correct.
Could anyone explain me how ignition handle history query and what I did wrong?