I have used IM for decades and have never had these two issues before:
1) You type in your integration and get all the mapping completed. You click the save button and then hit Run. You get the message that one of your source mapping fields is not defined. You know you set it because this now happens almost every time so you pay exttra attention to not only entering it, but moving to another field just to make sure.
2) What is the purpose of the UseOptimizedFiltering setting, in the IM.INI file? I have found that in integrations with a lot of records, IM will just skip transactions. I have gotten around this by setting this option to False and using an order by clause on my Advanced ODBC Queries. If all this setting does is break your integrations why even have it?
I have loaded the lastest service pack for IM.