A few users have been reporting that The Time Machine Mechanic (T2M2) throws errors when run sometimes. Although I cannot establish a simple underlying pattern, I think that this is most likely to occur when:

• running on macOS 10.13 High Sierra,
• no backup has been completed for over 90 minutes,
• T2M2 examines the DAS and CTS dispatching systems.

This may result from an undocumented change in the way in which the log command expects filter predicates to be presented, in High Sierra. However, as I don’t have any log records for these errors, and there has been no change in the documentation, I am working on a hunch.

I have tried to fix that hunch in T2M2 version 1.2, now available from here: t2m212
and from Downloads above.

Please let me know if this helps, or was not the right answer.