This is a product defect (32928).
This will be fixed in a future release of the product. If you require this immediately corrected, please contact Support for a hotfix referencing the defect ID 32928. Alternatively, #33343 should be requested, which is based on 8.1.3 and also contains #32928 and #33410. #33343 solves several other problems with 'ValidFrom' and 'ValidTo'.