Scheduled Backups only start, if task "ACRONIS TRUE IMAGE SERVICE (32 Bit)" has been ended before

Hello, I've encountered a strange problem:
I'm running Acronis True Image 2014 Premium Build 6673 on Windows 8.1 Pro 64 Bit.
I scheduled 2 daily backupjobs based on incremental plan (1:00 p.m system-drive and 4 p.m. data-drive) and a weekly backupjob. The first backup worked fine, but the second did not start. i searched for solutions, tried to run the acronis scheduler, reinstalled acronis true image, deleted the backupjobs and added new ones, disabled windows fast boot.... it seemed that scheduled backups were performed randomly only.
Even when I hit the "backup now" button, most of the time it seemed that the program tried to start the job, but did not do anything.
Later I found out that if I opened the Taskmanager and ended the task "ACRONIS TRUE IMAGE SERVICE (32 Bit)" (that automatically ends "ACRONIS TRUE IMAGE NOTIFY (32 Bit)" as well), the scheduled backups were performed as they should be. But this task kept running after a scheduled Backup was finished, so i need to end this task every time before the next scheduled backup should be performed.

Although I found a "solution" to get it work somehow, I don't think it should be needed to interfere manually in the process. Especially since i ran Acronis True Image 2013 Premium on Windows 7 Ultimate without any issues.
If anyone had an idea or solution for me, that'd be highly appreciated!
Thank you!