I received more than 5 reports about custom blocks not working correctly and every customer who reported the issue is using CustomCrops.
Remove custom crops and restore the "itemsadder" world folder from a recent backup. Fror example: world/itemsdder/
The developer of CustomCrops keep saying it's not an issue caused by their plugin but it's happening only to people using CustomCrops, so it's clearly some incompatibility we need to figure out.
I'd remove CustomCrops until the issue is identified and fixed.