The response of your "good" 2441 diaphragm looks to be normal.
Its rising response will flatten out somewhat when you put the 2308 ( slant-plate ) in front of the 2311 horn.
You might want to upload your REW file here so others can look at it for you.
Simply "Zip" it first so that the forum software allows it as a proper file type to be uploaded.
PS; There are a couple of places to change the vertical db scaling ( one is within a small icon that has 2 sets of arrows overlaying a rectangular box ).
PS2; The "bad" response is so off it has me thinking its not a bona-fide JBL diaphragm ( you might want to post a few pics so that others can help with that determination ).