Why Personal Zoom Links do not stay the same??!!

[MiroRendleman]

I have a company with 100 contractors' zoom account under my management. I absolutely double checked their Personal Zoom Linking one by one before paste into my company database. Today I am super surprised that 20 out of the 100 Zoom links do not stay the same!! And the most common type of changes are from https://us05web.zoom.us/***  to https://us06web.zoom.us/***

one from https://us04web.zoom.us/***  to https://us06web.zoom.us/***

and one from https://us02web.zoom.us/***  to https://us06web.zoom.us/***

This will cause a huge trouble for our future company operations because we highly rely on the "never change" Personal Zoom Meeting links. Can anyone help? or at least I need to know how often this change may happen. This drives me nuts.  Thank you!