Topic
After upgrading to 5.9, the Add Days function in form or view is not adding up the date correctly. This may happen only when opening the form directly, or it can happen when running the form in Designer and opening the form directly. If you have multiple environments upgraded to 5.9, this issue may only surface on a few environments and not all environments.
Instructions
During the installation or upgrade process, the installer will stop IIS and move/replace files. After completing this operation, the installer will restart IIS and rebuild the bundles and cache. However, if IIS is restarted by another process before this operation is completed, the bundle and cache gets rebuilt beforehand. This resulted in the forms and views using an outdated cache.
On the web server hosting K2 smartforms, go to [Program Files]\K2\K2 smartforms Runtime\Content, and remove all files inside the Content folder. This will clear the existing smartforms Runtime cache and force the cache to regenerate.
Perform IISRESET after that and check if the Add Days function is working correctly. Please note it will take some time for the cache to regenerate to it may take a while for your view or form to load after clearing the cache.
If this issue is also happening when you try to run the form or view in Designer, go to [Program Files]\K2\K2 smartforms Designer\Content and remove all files inside the Content folder.