It's pretty standard for banks to give higher credit lines on premium cards as they tend to make the most money from premium users. Your spending habits may be outside that standard. Have you tried messaging or calling Chase to reallocate some of your credit from one card to the other to match your spending pattern?

I have 4 amex cards (3 credit and 1 charge) I had a $8k limit on the no annual fee Amex Everyday, got a $19,500 on my Amex Hilton(14 months ago) and $15,400 on the SPG card (recently). Two weeks after the SPG card I got a notice from CreditKarma that Amex had reduced the credit line on my Amex Everyday to $3500. Obviously with the addition of the SPG card I had reached a credit tipping point for Amex, even though they issue me a new card without a credit check, and they reduced the credit line on the card I almost never used ($7.50 in past 15 months) and was the annual fee free one.