Scenario
Users have an item where the Quantity on Hand for a Location is in decimal places.
A possible reason could be that the item uses Units Of Measure and there were transactions (i.e.: Inventory Adjustment) which were using the wrong Units of Measure.
Solution
1. Open the Item record
2. Go to Related Records tab
3. Look for a Transaction where the Quantity is in decimal places
4. Edit the transaction
5. Check the Units column on the Transaction to see if it matches with the Units of Measure with the Item
6. If it doesn't match, change it to the one that the Item is using
7. Click Save