With the fuel issues we presently have, (lots of ethanol), this is becoming more and more common.
What is happening is, a vapor lock. The injectors are opening like they should be, but the fuel is more of a gas as compared to a liquid. This happens after an engine has gotten to temperature and then is shut off for a bit.
If you were to remove your seat so it would cool more efficiently while you had the engine shut off, I would bet you would not have the issue..
This is super common with traditional boats especially due to the hotter than normal summer that the US is seeing...