You might face the following error in purchase invoice creation in X3V11 after updating it with patch 18. Even though the dimensions are not mandatory at the account code level, you will keep on facing this issue and will be unable to move forward.
The bug is in patch 18 for X3V11.
You will need to download the hotfix from Sage and integrate it into the X3 and appropriate folders. Please follow the standard process for patch integration to integrate this hotfix.
The following dat file contains the hot fixes for patch 18.
Note: Patch integration process should be done through X3 folder.