The issue is definitely in the core of home-assistant. The delay offset seems to be related to the time of day. I suspect a memory leak somewhere that is corrupting the time trigger function. My “time” triggers fire at the same incorrect time everyday but are inconsistent in time offset from hour to hour.
Pretty sad when you can’t rely on “time” for automation triggers.
I found that “state” triggers work properly so that is the workaround until the programmers get to fixing this problem.
I had the same issue and actually found the problem for me (running HA 2021.8.6 on a 2010 Mac mini via a VirtualBox VM) was the “Paravirtualization Interface” option in the VirtualBox system settings. I had to switch it to “none” and that solved my time issue completely.
I am having a similar problem with automations triggering at odd times. But I am running on Windows Hyper-V. rather than VirtualBox. Can anybody think of an equivalent “Paravirtualization Interface” setting in Hyper-V that I could try?