sometimes when I log in and out of my world comparators that I use for my farms will stop working and I have to pick them up and place them back down for them to start working again

sometimes when I log in and out of my world comparators that I use for my farms will stop working and I have to pick them up and place them back down for them to start working again

the comparators should still work after I log in but they dont

instead they turn dark even though there is contents in the chest/dispenser they are reading and they don't put out a redstone signal

Steps to Reproduce:
1. log in and out over time or unload the chunks