I second this. It requires a restart UNLESS you can get a mob to hit you to interrupt your gathering:

Time: 01/09/2013 3:25 (GMT+10)
Frequency: Repeatable
World name:Masamune
Character name: Arkenshal Xiv
NPC name: N/A
Monster name: N/A
Class/Level:Miner 13
Party or solo: Solo
In-game time: N/A
Area and coordinates: Outside Copperbell Mines (Western Thanalan X:27 Y:17)
Steps:
1. Be using a controller on PC
2. Initiate gathering process
3. Start gathering items
4. During gathering process, open main menu (press start)
5. Close main menu
6. Gathering window disappears, unable to resume gathering. Unable to move as character is still 'gathering'. Chatting still works, nothing else does. Only way to fix is to get hit by a mob or to restart game.