Character is "spell-locked" for too long.

Platform: Windows
ISP: Videotron
Type of Internet Connection: cable
Internet Connection Speed: 15 MBs
Date & Time: Jan 4th 2017
Frequency: often
Character Name: Alanara
Race: Mithra
World: Odin
Main Job: Ninja
Support Job: Dancer
Area and Coordinates: Ru'Aun Gardens
Party or Solo: Party with 4 Trust NPC
NPC Name: -
Monster Name: Groundkeepers
Steps:
1. Traveled to Ru'Aun Gardens to kill Groundkeepers with Blade: Metsu as part of the Relic Katana's second trial.
2. Gained aggro of all Groundkeeper enemies that live in their sockets in the alley leading to the Shrine's main entrance (where Despot spawns)
3. Ran to the opposite end of the alley from the Shrine's entrance with all 16 monsters following me.
4. Stopped to engage monsters.
5. My character did not draw weapons through the first fight, but could still hit and kill the current target.
6. At this point, I could not move my character around.
7. Finally drew weapons, but still could not move. Auto-target selected a second enemy in front of me.
8. Killed second enemy, still could not move.
9. Auto-target selected 3rd enemy. No other enemy could be in line of sight to land a blow on.
10. Trust NPC could no longer support me due to being unable to move my character and face one to land a blow, resulting in death after about 5 minutes of being locked.
11. Constant attacks from multiple enemies at once should not hinder my ability to control my character.

I too have experienced this bug many on many occasions.

This happens a lot, especially when fighting multiple monsters at a time.

Here's an easy way to reproduce this effect, as it doesn't only occur in Ru'Aun Gardens:
1) Have a party of 2 players, one having a mage-type job that can cast support or healing spells. Let's call it "Mage" from now on. Other player can be of any job. Let's call it "Puller".
2) Have Puller aggro a large number of enemies (12-20 monsters) by running near them. Monsters that can detect by sound are easier to tag.
3) Have Puller stop running, and face enemies who are chasing him.
4) Have Puller use the "Attack" command to engage a targeted monster. Meanwhile, have Mage cast a healing spell on Puller, such as "Cure III". Ideally, the spell should land on Puller before Puller's animation of drawing weapons can play.
5) Note that while Puller receives the effect of the spell, he cannot move.
6) Try moving Puller around while monsters constantly attack him.
7) Notice that, as long as monsters constantly land a blow on Puller at a fast rate, Puller cannot move around.