What were you expecting to happen, and what actually happened
There is currently two glitches when upgrading farmer.
1: Similar to Miner and Merchant, the timer is reset to an hour when ascending them, as well as when leveling merchant and miner.
2: There is a unique glitch that seems to only be present with the farmer where sometimes when it it leveled the timer for the food will shift to have hours of it already completed. This often gives 100s of free food every level.
How often does this happen? When did it begin happening?
Always since the start of early access.
Steps to make it happen again
1: Level farmer after a couple minutes of the timer running.
2: Free food.