I noticed on long prints the left corners of my prints would lift more often than anything else on the build plate. I did some testing and when the auxillary fan is set to 70% by default it's still blowing a very strong concentrated stream of cooling air right across that side of the bed. This stream of air would hit the edges of the models and it forces them to cool sooner than the rest of your model on longer prints. I decided to make a diffuser style grill to break up the strong current of cold air across the model and make it a little easier on the part to reduce lifting.
I made different versions to suit your air flow needs and so far I prefer the 60% rectilinear but the others do break up the strong air current as well but allow different amounts of air flow across the bed. I'll post some videos of the air current testing I did with my diffuser installed versus another printer with nothing on the auxillary fan output and the difference is pretty dramatic. The air flow with no restrictions is very strong and turbulent and with this grill in place it's a gentle stream of air that's not as turbulent but still moves enough air to do the job.
To install: Start the back end of the rear fins into the slot just beyond the midway point then slide the remaining fins in and pushing them towards the opening until they're all inserted and tight against the front of the opening on the fan housing. You can adjust the fit and centering once the entire strip of fins is inserted. You will see that there is enough clearance for the toolhead to move in front of this diffuser but you have to make sure it's inserted all the way in and against the plastic fan housing.