Before I report this as a bug, would like to check if other people having the same problem, or is it a feature?
Version: 2.83.5, branch: master, commit date: 2020-08-19 06:07, hash: c2b144df395f, type: Release
build date: 2020-08-19, 06:05:02
platform: Linux Debian 9 AMD 64
Graphics card: NVIDIA Corporation GK106 [GeForce GTX 650 Ti] (rev a1)
Short description of error
Vertex extrude, ESC/cancel leave over lapping vertex behind, is this a BUG ?, Also When extruding, Mouse movement helper at bottom of window, don’t work during extrude, so misleading.
Exact steps for others to reproduce the error
Extrude vertex(s) then cancel using ESC key, leaves newly crated vertex’s over lapping origin vertex’s, requiring a remove over lapping vertex’s operation.
Second, minor problem during extrude, mouse movement helper shows, you can “Move/Rotate View/Call Menu”. Which dose not work. Hitting any one the mouse helper suggestions confirms the extrude, except the “Call Menu” which cancels extrude, but just like ESC key leaves over lapping vertex’s behind.
Comment: There may be a good reason for this, but ESC key is used for cancel current operation in just about every other CAD software out there.
The mouse helper at bottom of the window should show cancel/confirm extrude, IE: cancel and leave over lapping vertex’s behind, cancel with-out leaving vertex’s behind, and confirm extrude.
Not “Move/Rotate View/Call Menu”, which you can’t use. And adds extra layer of confusing( given that I’m new to Blender, and 63 year old it takes very little to confuse my 2 remaining brains cells! 
LOL.
lachlanA