PowerApps connecting to SharePoint allows you to build complex scenarios without having to customize the formulas, however there are times when you have specific business rules that need to be addressed.
SQL Server has many different ways (column types) to represent date/time values, and depending on which one is used in the database table, you may have some surprising results when trying to consume that in PowerApps.
PowerApps currently doesn’t support out of the box multi-valued fields – columns in a data source that can take zero or more of a predefined set of values.