Perhaps you've seen something about presidential behavior at the Dole memorial in the Capitol rotunda. The claim: it reflects bad blood between POTUS Biden and Veep Harris.
BizPac Review has video of the actual happening so you can judge for yourselves. What is indisputable is that, as marched in by the Capitol police, Joe Biden ended up adjacent to Vice President Kamala Harris. He then whispers to wife Dr. Jill, after which they exchange places so she, not he, is adjacent to Harris. Following the Biden move, Harris whispers to her husband. As everyone is masked, no lip reading is possible.
All of the foregoing is on the video. What is alleged is that Biden wished to disassociate himself from Harris, either in person or in photos of the event, or both. And that Harris perceives this snub and isn't best pleased.
Harris' poll numbers are so low they make Biden's less low numbers look not so bad. It is easy to imagine he doesn't want to be associated in the public mind with Harris.
On the other hand, the above conspiracy theory presupposes Joe Biden is sufficiently compos mentis to formulate this concept. Many have claimed otherwise.