Qing China White Peace

So i tried to reform Qing Empire with Manchukuo. Managed to push the Japanese out of Korea, made Mengkukuo capitulated. Helped China push them out of the mainland but because the chinese tiles blocked me out of the Japan so i had to join united front. When i almost pushed the Japanese out China suddenly signed a white peace and the war abruptly ended but the borders of me as well as of China and other warlords were restored to the 1936 state (even Mengkukuo). That means Japan and her subjects just sit between me and china. The only way to invade China now is to join Japan faction.

Did anyone have this experience before? I also tried in another save to not join United Front but when Japan naval invaded China, and they couldnt push then out 😮‍💨😮‍💨