change tabline buffer color after switching between files

[416207298]

At first, tabline color is drak, which is same as I set. But when I jump to another file to find a defination (using coc), the color of tabline becomes wired. Only when I use: :set bg=dark, It could back to normal again.

How to fix this?

before:

after:

[416207298]

also, it conflicts with lfv89/vim-interestingwords.