Here are the time's where I noticed it move or "twitch." It seems to strafe to the right then left back to where it started.
I only notice it swap the pole out for weapons once.
14:17:36 - Started fishing.
[F] 14:18:37 - [Spell] Cast Fishing (Fishing)
[F] 14:19:38 - [Spell] Cast Fishing (Fishing)
[F] 14:20:38 - [Spell] Cast Fishing (Fishing)
[F] 14:21:39 - [Spell] Cast Fishing (Fishing)
[F] 14:22:40 - [Spell] Cast Fishing (Fishing)
[F] 14:23:41 - [Spell] Cast Fishing (Fishing)
[F] 14:24:41 - [Spell] Cast Fishing (Fishing) - equipped weapon then switched back to pole then fished
[F] 14:25:42 - [Spell] Cast Fishing (Fishing)
[F] 14:27:44 - [Spell] Cast Fishing (Fishing) - added lure as well as move
[F] 14:28:45 - [Spell] Cast Fishing (Fishing)
[F] 14:29:45 - [Spell] Cast Fishing (Fishing)
[F] 14:30:46 - [Spell] Cast Fishing (Fishing)
No new lines in the log, even with all options set to on.
I'm not sure on the frequency. I will try to time it sometime this weekend. I'll post a log too of when I get it.