[snip]

I shall certainly check the battery but I don't see how the battery could caise so many "bad" log entries spanning several hours in one minute.
Look again at the snippet I included.
Cheers,
Stephen

[snip]

Good, this is just methodology starting with the battery.  Possible to expand your snippet of log to 10 lines before and after both time changes? Just looking for processes being started etc. etc.