Any known Issue with December 2018 Or November 2018 CU for SharePoint 2013
have anyone seen any issue with the CU update ?
Before installing these CU make sure couple of things.
It is always highly recommended that always apply the cu in lower farm and perform full testing.
The best source for this question is Todd Klindt's fantastic SharePoint 2013 Build Numbers page. You can find a column
Bugs, Notes and regressions for every patch.
Your noted patches do not have any specific drawback, except the .NET Security Patch issue. But this is not a SharePoint-CU specific issue, it was caused by a Windows .NET Security Patch.
This also matches my personal experience. No bugs have been reported by customers.