Qlik Sense Chart Calculations Incorrect After Upgrade to Sept 2018

An application was developed on the April 2018 release of Qlik Sense and was working fine. After upgrade to September 2018, the application had issues with charts; calculations were different when using the same set of data. example: would get 1% as an answer in sept 2018 but with the same data and the same app it would be 45% in Sept 2018 version. 
Environment:
Qlik Sense Sep 2018 after upgrading from April 2018

The issue was found to be directly related to  use of a field named "Year" which was a calculated dimension. Having a calculated dimension with the same name as a built-in function is not a good practice as there could be situations where the two would be confused by the Qlik engine. This had worked ok in the previous version but as a best practice a different field name should be used for the calculated dimension. 

Changing the name of the field from Year to Year2 resolved the issue.

1. A new field was added in the load script using an AS statement ( example: YEAR("Date of Notice") as Year2, )
2. Then the new field year2 was dragged onto each visualization from the list of fields and replaced the old field named Year. 
3. Then the existing expressions were updated to use the new field name. Note the example below; every occurrence of year was not replaced, just the ones that corresponded to the old field named Year. The other field names which include the word year were not changed.

Example of updating one of the expressions to use Year2.

Original:

Count({<Actions= , Year={"<=$(=Max(MaxYear))>=$(=Min(MinYear))"}>}ClaimID)/Count(TOTAL <Year> {<Actions= , Year={"<=$(=Max(MaxYear))>=$(=Min(MinYear))"}>}ClaimID)

New:

Count({<Actions= , Year2={"<=$(=Max(MaxYear))>=$(=Min(MinYear))"}>}ClaimID)/Count(TOTAL <Year2> {<Actions= , Year2={"<=$(=Max(MaxYear))>=$(=Min(MinYear))"}>}ClaimID)

This allowed the chart to be updated to the new field and the calculations were equal to the past version.