Possible humbucker issue

I need some help. I recently purchased a used EBMM Stingray SLO Special. I tested the bass to make sure it worked. I cleaned up the ray and put a new set D’Addario nickel strings. I tested the bass by playing it along with some tunes I like to play for practicing etc. I noticed that the E string is not as loud as the A and D strings. The G is not as pronounced either. The strings are leveled evenly above the humbucker.

I tried using a different set of strings that I had available and that didn’t help. I changed out the E string with a different E string and the pickup did not produce the same level of output as the A, D, and G strings.

Another reason why I’m in question about the pickup being faulty is that I had a 5 string Stingray at the beginning of the year and the E string was great no problems. I suspect there is an issue with the humbucker.

The D’Addario strings may not be proper for the Stingray I’m open to some suggestions. I was going to buy a set of DR Lo Riders to see if it will sound better. I have changed the battery yet, but I don’t think that is the problem.

What do you all think? Does Ernie Ball provide repair services? Any helpful suggestions welcomed.

Thanks,