FPS Capped at 60?

Just back from AFK yesterday.

I found my game was capped at 60 fps, for no reason.

I checked:
VSYNC closed,
fps limiter at 120
fps limiter in RTSS(afterburner) @120
other setings not found

I have my graphic card as 1080TI, wihle it is loaded at 50%, and my 9700K at 35%.

I remember last time I played this game, everything goes fine.

Generally I play this game in windowed fullscrren mode, and its caped at 60. Somthings interesting is that when I switch to fullscreen mode, then it capped at 120 as I expected.

Any suggestion?

Monitor is set to 60hz? fullscreen vs border?

Monitor is 120hz for sure, and I played other games at 120pfs normally.

The situation is that I has POE with 60fps at windowed mode (both border and borderless), and once I switch to fullscreen mode, then it can reach 120fps, with out any other changes.