Refuel light comes on after dealer recall update

So the other day I took my 2018 Tundra in for a recall. It was an update but can't remember for what.
Anyways as I drove off the lot I noticed my fuel gauge read refuel even with half a tank.
I called the dealer and he said he's seen this after some updates and should go away.
The problem is my Tundra is up for sale so not a good thing to have this problem. So far I've only driven a few miles as I don't want to put many on. I did take off the gas cap and was thinking about disconnecting the battery to see if that fixes the problem.
I would appreciate any input on this.

 

I would try disconnecting the battery for 30 minutes and see if it clears.

 

I believe that recall was for something fuel tank related and they want it almost empty to do the service. I think if you fill up and charge the guy an extra $100 on the sale price then you should be fine - good luck,

 

Thanks !
In a panic today because I had 3 people coming to look at it so I went for a drive on the hwy thinking if I put a few km on it, it would straighten itself out. Low and behold after 10 min I watched it change from refuel to 355km distance remaining ! I was so happy lol. Looks like all it needed was a few km of driving.

Thanks for the comments

 

I recent noticed my fuel gauge would drop slowly to Empty (while in drive and also while parked) prompting a refuel light to engage. Even after I had a little over 3/4 tank. At times the gauge would go back up to a normal reading and then back down again some time later. Any ideas or has anyone heard of anything as such?