No problem, asking questions on here gives you answers from several people, mind it they may be different and be debated but that's what these forums are for.  

12# CXX is NOT 12 pound line! It's a 20# line. It has the same diameter as 20# Tatsu, and 20# line is pretty thick for bass-sized baitcasters. KVD L&L works well.

1. You are overfilling your spinning reel.

2.  You are not treating the line with a line conditioner as you spool fresh line.

3.  You are not spooling the line counter clockwise.

4.  You are getting line twist.

5,  Your line test is too high from your baits.

6.  You did not soak or run hot water over the spool with the fresh line in hot water for three to four minutes.

7.  Your reel size may be too small for your techniques. A 2500 size is excellent for bass fishing.

8.  You are not spooling some braid on your spinning reel first and then spooling the mono or fluorocarbon line on top of it.

 

Try the hot water trick and see if you don't see improvements.

 

Having the line flip off the spinning reel spool is a normal occurrence and you have to mitigate it as you fish.

And one last suggestion.

 

After you have set up your spinning rig, take it outside and tie the end of the line or use your hook to secure the line to a tree or pole or something to hold it.

 

Walk off as much line as you wish and with the drag set pull, pull and pull the line three, four our more times.

 

Hold the line in full stretch for a few seconds each time you pull the line.

 

Then, place the rod on the grass and walk back to where you have secured the line's end and untie the line.

 

Walk back to your spinning rig and reel in the line using your fingers to have the line return to the spool in a tight manner.

 

You also try to reel in your line in a tight manner when fishing to avoid the line twist.

 

After reeling in the line you should be ready to rock and roll with few problems until you get the line twist from your baits.

 

Give some of these suggestions a shot and let us know if they improve the situation.