Issue with Merge Column in Waterfall Causing Credit Overuse

Clay S. I am having an issue where the merge column on a waterfall is not combining whichever email provider was successful in finding a validated email address. I added one additional waterfall step and the outputs are not consistent and some are missing in that merge column. this is causing a large amount of additional credits used and contacts not moving on to my outbound campaigns. Table - https://app.clay.com/workspaces/267746/workbooks/wb_0sxo05rGeAJxt3ax4DF/tables/t_0sxr83zD5wmq8u8s86R/views/gv_0sx7n1oJthuE4bHmamw