Avaya OD node arrangement changes after upgrade from 6.0 to 7.2,
Nodes changes position and sometimes overlap.
But its not due to OD upgrade but something else as I installed OD 7.2
on old server and there I see they arranged properly with spaces.

How to correct it and what is causing the issue?

Hi.
First step is to check all the imported projects: can they run fine on
the new AAOD 7.2 ? If the answer is yes, the import process was succesfull and
probably the issue is related to the old server.

If nodes seem to be squeezed together, use the buttons (Blocks and
Lines) toward the right side of the main toolbar on top to align the
nodes (Align Left/Align Right/ Align Top/Align Bottom/Align Middle) or space them out automatically (Distribute Horizontally/Distribute Vertically).

If you are using, on that old server, a screen/monitor with a
different resolution, the display on all of the flows could overlap
and smash together. Check the monitor resolution. The minimum
requirement is 1024 pixels in width and 768 pixels in height. Please,
take a look at

https://documentation.avaya.com/bundle/GettingStartedwithAvayaAuraOrchestrationDesigner_r723/page/HardwareRequirements.html

Also take a look at

https://www.devconnectprogram.com/forums/posts/list/25430.page#p164745

https://www.devconnectprogram.com/forums/posts/list/21179.page#p150080