Here is one way of how to reproduce my issue:
1. In a new file with sample data, add the Notes column to the Welcome Grid.
2. For the "Item" Field Properties, add conditional formatting:
Criteria: [Notes]="work"
Formats: BackColor=&H00FFFF
3. Close and reopen the Welcome Grid
4. Type work in the Notes column for an item => Item gets yellow highlights as it should.
Now edit the Criteria to [Notes]="Work" (capital W)
3. Close and reopen the Welcome Grid
4. Type Work in the Notes column for an item => Item does not get yellow highlights as it should.