Looks like he had another *freeze* moment.
Based on my personal experience I’m of the opinion that Biden has a complicated case of Parkinson’s Disease. Note the awkward arm position as he stiffly and slowly walks. Every now and then you can see tremors in his right hand. As we know from his short work days he fatigues easily. After he’s been at a podium for a few minutes he tends to stoop forward. His cognitive decline suggests he may have Lewy Body dementia.