I looked at the original weibo more carefully.The images say nothing about the new bomber, but the person who shared it thinks this has something to do with the completion of RCS tests. The poster apparently has some credibility.
1, this is the test project of some flight control system, which lasted for 6 days
2, it mentioned during trouble shooting phase, the test team worked together with "XAC test flight institution" as well as "general assemly plant"
3, leader of the 618 institute Song Ke Pu visited the site and boarded the aircraft(登机检查）
Now, how do we make of these?