strange staff!!

[Mart!jn]

today i decided to change from the 1th flottila to the 2nd flottila.
i applied and my request was approved.
so i click on to the mission, briefing:
Patrol grid NULL
flottila: 7th

strange, what does it mean when i am ordered to patrol grid NULL
and when i apply for the 2nd flotilla i go the the 7th, strange!
is this some kind of bug?

afther this, i decided to do the mission. my base was changed to brest! very strange cause when i applied for the 2nd flottila, my base changed to st Nazaire. well i did the mission but i decided to exit the patrol when i just left the harbor of brest. then i applied again for the 2nd flotilla and now my request was approved again. but when i now want a mission everything is normal, i can even get a IX/B type.