When you apply the stonework structure exhibit - geologists currently out have their search time extended.

I had three thorough geologists out and their normal search time is 16 hours - they are showing 18 hours now. The same thing happened to two I was going to have come back in 2 hours, they are now showing a 3 hour return time.

https://imgur.com/a/8F71u6E

Actually refreshing the game just reduced the time down to 8 hours and brought the 2 at 3 hours back - unfortunately they had nothing to fill but would have had in 2 hours...

I had a similar thing happen to romantic explorers during the event - they had search time extended by applying I think a PFB but I had taken no screenshots and wasn't 100% sure.