Why might I be getting non-90 degree vertical lines from push/pull tool?

And in recent versions of SU, Down arrow for parallel/perpendicular (purple or magenta colour).

Thanks for the info. I was unaware of that.

It’s been true from v2016 I think. In older versions, if you got a magenta inference, you could ‘hold’ it using Shift. And Down Arrow used to do the same as Up Arrow - hold on blue axis.