TIH 2013 [6514] backup will not start after target disk is disconnected, then reconnected with same drive letter

I run a scheduled backup [Disk image; Incremental; New Full after 5 incr; No more than 1 backup chain] daily from a laptop connected to my target USB disk via a docking station. If I undock the computer for travel, then return and redock it, the scheduled backup does not run and does not return an error message; furthermore, the backup task will not start manually after redocking either.

The target drive retains the same drive letter and identification after re-docking, and it is recognized within TI, and other TI functions (verify, mount volume, recover, etc.) behave properly after the computer is reattached to the docking station, but backup will not start. The software acts as though it never received the request to perform a backup. Windows Explorer and other disk related utilities appear to work properly.

So far the only remedy I have found is to rerun Acronis.scheduler.8216.exe, and then start the backup task manually. After that, the scheduled task performs as intended. The environment is as follows:
HP EliteBook 8570 W [24 GB memory]
HP 230W Advanced Docking Station
Windows 7 professional 64 bit(Service Pack 1)
TI Home 2013, Build 6514
Target: Drobo Mini (4 TB total;~3 TB usable; 64 TB virtual ] - USB 3 connection to docking station.

Any suggestions to avoid reinstalling the scheduler every time I undock and redock? Or failing that, how can I run the reinstallation automatically as part of the backup job? Thanks for your help…