Anyone else have this issue? When i start up the car in the morning I notice it’s about 20-30 min ahead. This has been happening ever since last week and I can’t figure out why. I went into setup and turned off the auto adjust feature for the system time and set my time zone correctly, but I’m not sure if system time and the clock are synced. I’ve looked around online but no one seems to have posted a definitive answer.

2015 IS 350 f sport. 54,000 miles

 

I also noticed clock is messed up on my 2015 350

 

To partially answer your question, a 2015 IS clock is not synced to the system time. This feature was added in 2019.
So the clock is really an entity onto itself...maybe the issue is just the clock. Perhaps set the time to the current time and monitor it for a couple days as see what happens.
Any chance something spilled on the buttons to adjust the time? I know that's a long shot, but never hurts to ask.

 

My 2014 had this issue, but the 2016 did not. It may have been a coincidence, but the battery on the '14 died not long after the clock started running fast.

 

Nope, never spilled anything into the buttons or clock. I’ll check to see what happens if I don’t adjust the clock.

I’ll check my voltage today.

 

My 2014's clock starting running fast after a couple of years. It was replaced under certified warranty. No issues thus far with the new clock. Service rep noted at the time 'looks like another clock'... so this may have been quite common around that time.

 

If I don’t reset the clock it just get further ahead. Overnight twice resulted in almost an hour ahead.

 

Lexus really needs a digital clock alternative for the F-Sport.

 

It sounds like it's just the clock.

 

The clocks running fast or slow is a common issue with IS ES GS and LS models.