Usually, just deleting the cookies will sort the missing historical EPG.
Press the “Freeview Play” (F) button and select Players. At top right, there should be a blue “i”, which you select. Then press “+” and follow the prompts. The EPG should then be available.
Or hdmi-cec is active on TV/Humax/anything else connected, and when you turn off the Humax and then (let’s say) change channel on the TV, its triggering the signal to turn the Humax back on again?
I unplugged it for a minute. That seems to have worked.
The Humax is normally on all day, & switched off at night, along with the TV. I noticed in the morning that the blue light was on, so I switched off. Two minutes later, it was back on. Switched off, & the same thing happened again!