Guild Wars 2

Our guild has had the first guild stash for awhile. A few days ago we began researching the architecture level 3 for 5K. At the time there was a second guild stash for 5K listed under it. Once Level 3 finished the storage increase option originally displayed disappeared.

The wiki says total guild storage is 250 items. A second stash of 50 would make that 300. So why was it displayed and what’s the point of a level 3 architecture research if it doesn’t unlock anything, except absorb influence?

No one has an answer for this? Should I move it to guild section if it’s not a bug?