Steps to reproduce:
Change timezone on server:

date -s "29 OCT 2017 03:50:00 EEST"

Create item with configuration like on screenshot with example (update interval 0, scheduling interval "m0-59").
wait till timezone will be changed to EET (timezone should be changed at 04:00 EEST)
Result:

mysql> select itemid,count(*) from history group by itemid;
+--------+----------+
| itemid | count(*) |
+--------+----------+
|  25366 |    46427 |
|  25367 |   364358 |
+--------+----------+
2 rows in set (0.12 sec)

Expected:
The item should be processed with one minute time interval, but scheduling interval does not work properly after winter time change and generates many duplicate values in DB.