Lean running after hot-start

[Opelotus]

Hi everyone, been awhile since I've posted here.

1984 US spec with Bosch L-JET. I've had the car for 10 years and it has always been reliable as far as starting and whatnot, but the past year or so, I've noticed it doesn't like to hot- start. Initially I thought it was due to a leaky injector (injectors are reman, were installed 4 years ago. All dampers/regulators are also less than 5 years old) due to a slight smell of fuel after 10 minutes of the engine off. Symptoms are extended cranking, then stumbling for a minute or two, and low idle speed. Anyways, after installing a wideband AFR gauge, I see that it is actually running very lean (around 18:1 when it first restarts hot). Takes a couple minutes of driving for it to drop below 16:1. Any ideas as to why that may be? It otherwise idles around 14.8-15 AFR after the hot start clears up.

Also worth noting that the fuel pump and filter are brand new OEM as of a couple weeks ago (replaced as preventative maintenance). I just picked up an Arnnworks fuel pressure tester to check pressure in the rail. Vacuum lines are fairly new silicone and in good shape, so I don't think it's a vacuum leak issue, plus I'd expect it to run lean all the time if there was a leak there. Temp II sensor is 6 months old (Bosch).