If you use an attribute "Entry" then the internal variable "entry time" will expand to the last value of
"$Entry"+" time", e.g. if you use it in "Thread display = $entry time, ..."

One side effect is, that the logbook selection page defaults to use
Last submission = $entry time by $author
Which then expands to an undesired result.

This is not really a bug, rather something you'll need to keep in the back of your mind.