SQL C# CLR Table Valued Function slows down even though code didn't change!

I created a a SQL C# CLR table valued function which gets called inside a stored procedure. This was taking 9 seconds to run on a record set of 250000 records.

Without changing the record set or the code, the stored procedure now runs in 1 minute 19 seconds. I have checked and the time is taken up by the same CLR TVF.

I even restarted the SQL Server instance to remedy the problem but the function still takes more than 1 minute.

Any idea why this would happen?

Thanks for your help in advance.

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