Some issues about the "h1n1_ucld.tre"

[DuPanxin]

Hi,

Sorry to bother you! But I really encounter some issues that you can help me.
First, when I open the "h1n1_ucld.tre" in FigTree, I find the posteriors in some nodes are very low, for example lower than 0.1. Are these regular? What are the reasons? And recently, I encountered the similar issues when analyzed the human mt genomes.
Second, I find some branches are cross, that means the dates are disordered? Are these regular?
I attcahed the figures of these issues.

I would appreciate if you can help me.

All the best,
Panxin