Graphs die / stop charting at 4am every morning

Starting about 3 days ago, without any configuration changes from me, home assistant “stopped graphing things” after 4am. Rebooting fixes it until 4am the following day, i have no idea why this has begun, and as of this morning ive created an automation that just reboots home assistant at 4:01am until i can figure out whatever is causing this issue.

its not a load thing, its not a storage space thing, i dont have any automated jobs doing anything at 4am, and it started after the most recent two home assistant updates (the 4th and 5th, i think).

Interestingly, all the sensors that generate the numbers for all the charts (literally all the sensors in HA) still report the current value. So looking at a dashboard without any graphs you wouldnt have any idea that theres something wrong - but for some reason at 4am every morning HA just ‘stops writing to its own history’. You can see live data, but from 4am onward, no historical data. its super bizarre.

is anybody experiencing the same thing?

Did you upgrade to 2024.7? Sounds like this:

Hi,
I have the same issue since 4 of july.

Same issue here.

Not often you get hits that have the answer on a super specific Google Search for Home assistant stops at 4am.

Will try @MattB314 answer and see how it goes.