Dodge ram starting up issue

I have a 2016 dodge ram 1500. When I go to start it sometimes it will rev up for like 4-5 seconds before finally starting like it’s struggling. This only happens when I get off my 10 hour shift and when it starts getting warmer outside, never happens in the morning when I go to work, never happens if I just go to the store or get out of the store, just when it sits in the parking lot for my shift. Any ideas why this is happening?