surface tension.
there's nothing about the video that's inconsistent with a glass of water in space.
and here's the video of them preparing for the livestream.
ie, filling the glass and attaching it to the table with doublesided tape.
https://weibo.com/tv/show/1034:4786138817429591?from=old_pc_videoshow
or maybe there's a vast international conspiracy to lie to people about easily verifiable phenomena because nobody on a flat earth would pay taxes for some reason.
