The quantity on hand of both inventory report and in the product and services should match, even if there are transactions created for the specific inventory.
Here's a sample screenshot for reference:
We can perform some troubleshooting steps to check if this is caused by a browser-related issue. To start, open your company in a private browser or incognito window. This mode doesn't store cache, which usually causes unexpected behavior in a browser.
You can use these keyboard shortcuts:
Google Chrome: Ctrl + Shift + N
Mozilla Firefox: Ctrl + Shift + P
Safari: Command + Option + P
Next, try to run the Inventory Valuation Detail report and Product and Services. If you see the correct quantity on hand, go back to your regular browser and clear its cache. Finally, restart your browser.