Home depot now has the 594-135 in stock. I purchase three yesterday.
Where Can I Find Photocell Replacement Component SKU #594-135 For Hampton Bay Sku's 240-336, 240-339, 248-520, 248-521, 257-711, 672-664, 672-765, 673-255, 769-290, 769-557, 769-873. Home Depot No Longer Carries The SKu#594-135?