Hi All ,
Interesting problem , please look at the scene. I am using the old trick of using UVs and a ray sop to stick particles to a spherical surface. For some reason I get particles flying off out of UV space , even though I am using a point sop with clamping points to a $TX & $TY to zero to one.

I would love to know why points fly off and why the points disappear sometimes while on the surface.

On a another note I have also noticed is if I use a UV projection SOP and initialize it on the geometry I never get my UVs shrinking to fit into zero one , they are always just offset, surely no matter what the UVs should fit precisely within zero to one. Is there a reason for this ?

best r
h10.0.464 osx