2019 RAV hybrid system malfunction twice with only 2500 mikes

My leased 2019 Rav Hybrid has had a complete
system malfunction twice with only 2500 miles.  At
500 miles it was hauled into the dealer as it
wouldn’t start.  The dealer couldn’t find anything,
cleared the system and told me they didn’t think it
would happen again but no guarantees.  About 1
month later at 2500 miles it did the same thing.  
The message of each system saying system
malfunction contact dealer just kept cycling.  It’s
now been at the dealer for over a week.  The
mechanic says they can’t get it to replicate the
problem but they’re going to keep trying.  It looks
Ike another week.  Any ideas on why this is
happening.?  Crazy as I haven’t even had the car
for 60 days!