Seeing different long term capital gains tax rate

Before entering my Capital gains:

Total Income: $409,389

Deductions: 26,265

Taxable Income: $371,134

Federal Credits: $2,000

Federal taxes you Owe: $81,740

Refund shown was: $4,343

 

After entering my Long term capital gains of $52,150

Total Income: $461,539

Deductions: 26,265

Taxable Income: $423,284

Federal Credits: $0

Federal taxes you Owe: $91,877

Tax Due: $7,794

 

My Long term capital gains are within 15% tax bracket. So I would expect the tax on $52,150 to be $7823.

Why am I seeing going from a refund of $4,343 to Due of $7,794 (a change of $12,137).

 

ps: I am using Turbo Tax software.