Using the DBCC LOG command, I carefully monitored the size of a particular database log.
4:27 PM - 32,133
4:34 PM - 33,169
4:36 PM - 33,500
4:42 PM - 35,143
4:45 PM - 2,008,661
Seems like between 4:42 and 4:45, the log gets PACKED with the following row:
OPERATION= LOP_SHRINK_NOOP CONTEXT=LCX_NULL
The question is, what is LOP_SHRINK_NOOP ? I can't find information on this anywhere.