Recently we have noticed that ALTER ASSEMBLY is not updating the dll on the SQL Server. We have been altering the assembly since last two years and never had an issue before. The major change we have done is upgraded the targetted framework on the assembly to 4.8. I don't think this is an issue because we were able to alter another assembly on which we have upgraded the framework to 4.8. We have even decompiled the assembly and validated that our latest code is part of it. When we tracked the ModifiedDate in sys.assemblies, realized that the dll has not been updated. It is still pointing to the old date, while the other dlls got a latest modified date.
No errors or warnings are logged on the SSMS and SQL Server event viewer while running the Alter Assembly. We are not sure why is the assembly not updating. Please help us in resolving this issue.