Long crazy backupfilenames with a guid in it?

I have a backup task created with the filename "MYPC_HDD_C_SYSTEM".

If I run the backup task a filename like this is generated:

MYPC_HDD_C_SYSTEM.tib_9569709B-6FAB-4AE4-92FB-7908C6D22DFF.tib_C64CB935-D615-48EE-A749-B0954995843F_full_b2_s1_v1.tib

What the hell does that crazy name means?

I have fixed it some times but I have to redefine the whole backuptask.
After some weeks of backups the same issue appears again and again.

How can I fix it without redefine the whole backup task?
Where are this settings stored and maybe can they manually corrected?

Thank you all for every help ;-)