I've been playing with Alleys (Survival Mode). Got 2 from the Pillager outpost.
I lost the 2 but they all died in interesting ways.

Flowing Lava:
When going by lava or near lava (Flowing Lava) they would get burned.
This happened when I went to the Nether that I noticed this.
They (Alleys) Would not go Around and near the Stairway flowing water they would glide down and up and hit lava, and burn a little. 

Flowing Water:
Alleys would drown in Flowing Water. one got stuck when I was going back up flowing water, this is when I was exploring the Amazing Lush Caves.

Glass Pane and wooden Fences:
As we all know villages have stained glass panes and wooden fences.
The Alleys Would get stuck in there and would not go around them. I would come back to Find them there.

RIP, My Alleys but, this is how I was able to make this Bug Report.

Side Notes:
I play in Java Edition, so New to Bedrock.
I know Alleys are new, but they have a odd behaviors.

• • Note blocks:*
       A: when notebook was obstructed Alley would still try to place item ontop or through a Solid block drop the item.

I'll Reply when I Can...
Sincerely, Instantout