unexpected membrane printed inside open bell

[peterrewald]

I am trying to print an engine bell from a Saturn V rocket, using a Mars 2 Pro.  I admit I am very new to 3d printing.
When I view the image in Chitubox, I can see all the appropriate details inside the engine bell.  However, it prints out layers of 2mm membranes across the inside of the engine bell.  It skips about 3mm then does it again.
I have no idea where this is generated, nor how to get it to stop.
Has anyone else seen something like this?

[cliffyk]

You need to make some "vent" holes in the bell at the closed end to allow resin to drain between layers--else suction will trap it and light scatter from the curing lamp will partially cure the trapped resin: