LCD timer display bug?

I just noticed what seems to be some sort of bug with the LCD display - both the physical one and the virtual one in the webpage. The third BrewPi I set up to test DanF’s I2C LCD code doesn’t have any heat or cool abilities and is just sitting on my desk with two DS18b20 probes, so it can only idle. I noticed this morning that it seemed like it had reset its idle timer, but dismissed it as maybe it got reset somehow last night. Nothing has changed with it all day, and this afternoon it was reading something like 16 hours idle, but as of now, it’s just coming up on 12 hours idle. If it had been reset somehow, it would be less than 6 hours idle. I’m not sure where it reverts, but if I had to guess, I’d say around 20 hours idle, and it seems like at that point, it reverts from 20 hours to 10 hours.

Has anyone else noticed this behavior?

The timer does overflow after a certain time. We decided to not address this as it would grow the code size and it was already very limited on the Arduino.